FN Thomson Reuters Web of Science™ VR 1.0 PT S AU Smith, JG Connell, JW Hergenrother, PM Criss, JM AF Smith, JG Connell, JW Hergenrother, PM Criss, JM BE Repecka, L Saremi, FF TI High temperature transfer molding resins - II SO 2001: A MATERIALS AND PROCESSES ODYSSEY, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 46th International SAMPE Symposium and Exhibition CY MAY 06-10, 2001 CL LONG BEACH, CA SP Soc Advancement Mat & Process Engn DE resin transfer molding; high temperature polymers; polyimides; phenylethynyl containing imides; composites; carbon fiber composites; oligomeric thermosetting imides ID TERMINAL PHENYLETHYNYL GROUPS; IMIDE OLIGOMERS; COMPOSITE PROPERTIES; POLYIMIDE OLIGOMERS; MOLECULAR-WEIGHT; ADHESIVE; PENDENT; ANHYDRIDES AB Phenylethynl-containing imides (PEI) have been under investigation as part of an ongoing effort to develop materials amenable to composite fabrication via resin transfer molding (RTM). Uncured resins with low and stable melt viscosities and when cured high glass transition temperatures (Tgs) and acceptable toughness are needed. These materials are potentially useful as high performance/high temperature composites for advanced aerospace vehicles. Several PEIs were prepared and evaluated for melt flow behavior and mechanical properties after thermal curing. Candidate materials exhibited melt viscosities of 0.4-1.0 Pa .s, excellent melt stability (>2 hrs), at 280 degreesC, cured Tgs greater than or equal to 295 degreesC, and good toughness. Flat, void free composites were fabricated via RTM and tested. The chemistry, physical, and mechanical properties of these resins will be discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Smith, JG (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 33 TC 5 Z9 6 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-90-5 J9 INT SAMPE TECH CONF PY 2001 VL 46 BP 510 EP 521 PG 4 WC Engineering, Chemical; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Materials Science GA BS96V UT WOS:000171526800046 ER PT S AU Thompson, CM Hergenrother, PM AF Thompson, CM Hergenrother, PM BE Repecka, L Saremi, FF TI Phenylethynyl containing arylene ether oxadiazoles and triazoles for high performance applications SO 2001: A MATERIALS AND PROCESSES ODYSSEY, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 46th International SAMPE Symposium and Exhibition CY MAY 06-10, 2001 CL LONG BEACH, CA SP Soc Advancement Mat & Process Engn DE poly(arylene ether)s; phenylethynyl terminated oligomers AB As part of an effort to develop high performance polymers with a unique combination of properties (e.g. processability and mechanical performance) for future NASA applications, several novel phenylethynyl terminated arylene, ether oligomers containing oxadiazole and triazole units were prepared. The oligomers displayed low melt viscosities and good solubility. Thin films cast from solutions of the oligomers and cured for one hour at 350 degreesC in air gave good tensile properties. Titanium to titanium (6Al-4V) tensile shear specimens were readily fabricated and provided moderate strengths. The chemistry and properties of these new materials will be discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Thompson, CM (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-90-5 J9 INT SAMPE TECH CONF PY 2001 VL 46 BP 522 EP 532 PG 3 WC Engineering, Chemical; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Materials Science GA BS96V UT WOS:000171526800047 ER PT S AU Meador, MAB Sutter, JK Leissler, G Shin, EE McCorkle, L AF Meador, MAB Sutter, JK Leissler, G Shin, EE McCorkle, L BE Repecka, L Saremi, FF TI Coatings for high temperature polymer composites SO 2001: A MATERIALS AND PROCESSES ODYSSEY, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 46th International SAMPE Symposium and Exhibition CY MAY 06-10, 2001 CL LONG BEACH, CA SP Soc Advancement Mat & Process Engn DE coating; polymer matrix composite (PMC); and polyimide AB New erosion and thermo-oxidative coatings for polymer matrix composites (PMCs) used in gas turbine engine applications up to 280 degreesC were prepared and evaluated. T650-35/PMR-15 graphite fiber composites were plasma spray coated using a system comprised of a soft bondcoat and a hard topcoat. The bondcoat was made up of zinc with up to 5% polyimide added to improve the compatibility between the PMC and the topcoat. A design of experiments approach was used to study coating durability (measured by weight loss and tensile adhesion tests) as a function of weight % polyimide in bondcoat, aging time, and thermal cycling time, thus the number of cycles in air. Various damage types were identified, quantified, and then correlated to potential mechanisms. Mathematical modeling with the damage quantifiers, was attempted for performance and durability prediction. The most critical parameter controlling damage was the number of thermal cycles that the sample saw during aging. The addition of polyimide to the bondcoat provided a modest improvement in tensile properties after aging. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Meador, MAB (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. OI Meador, Mary Ann/0000-0003-2513-7372 NR 6 TC 2 Z9 2 U1 0 U2 2 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-90-5 J9 INT SAMPE TECH CONF PY 2001 VL 46 BP 572 EP 585 PG 2 WC Engineering, Chemical; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Materials Science GA BS96V UT WOS:000171526800051 ER PT S AU Bowman, CL Sutter, JK Thesken, JC Rice, BP AF Bowman, CL Sutter, JK Thesken, JC Rice, BP BE Repecka, L Saremi, FF TI Characterization of graphite fiber/polyimide composites for RLV applications SO 2001: A MATERIALS AND PROCESSES ODYSSEY, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 46th International SAMPE Symposium and Exhibition CY MAY 06-10, 2001 CL LONG BEACH, CA SP Soc Advancement Mat & Process Engn DE polyimide; graphite fiber composites; mechanical properties AB Polyimide matrix composites have been used successfully in aeronautic engine applications at temperatures of 290-315 degreesC. Extending these materials to Reusable Launch Vehicle applications will require higher operating temperatures for shorter duration. In this paper an eight-harness satin weave T650-35/PMR-II-50 composite has been tested at temperatures of 260-480 degreesC. Composite quality was characterized through destructive and nondestructive techniques. Uniaxial tension, creep, and tension-tension fatigue tests were conducted in the temperature range of 260-480 degreesC on dry specimens. Tensile strength degradation at temperatures below 480 degreesC was minimal; the elastic modulus was essentially constant below 385 degreesC. Fatigue results presented include stress life data and the cyclic degradation of tensile and compressive moduli. Furthermore, the temperature for onset of steam delamination was determined as a function of moisture content and heating rates (0.6 degreesC/min to 6 degreesC/min). The tensile modulus, compressive modulus and residual tensile strengths from both dry & moisture-saturated specimens were similar when tested below the macroscopic delamination temperature. C1 NASA, Glenn Res Ctr, Cleveland, OH USA. RP Bowman, CL (reprint author), NASA, Glenn Res Ctr, Cleveland, OH USA. NR 10 TC 10 Z9 13 U1 1 U2 1 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-90-5 J9 INT SAMPE TECH CONF PY 2001 VL 46 BP 1515 EP 1529 PG 3 WC Engineering, Chemical; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Materials Science GA BS96V UT WOS:000171526800136 ER PT S AU Blackwood, JR Townsend, JA Hansen, PA McClendon, MW Dever, JA deGroh, KK Reed, BB He, CC Peters, WC AF Blackwood, JR Townsend, JA Hansen, PA McClendon, MW Dever, JA deGroh, KK Reed, BB He, CC Peters, WC BE Repecka, L Saremi, FF TI Hubble Space Telescope third servicing mission retrieved metallized teflon FEP analysis SO 2001: A MATERIALS AND PROCESSES ODYSSEY, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 46th International SAMPE Symposium and Exhibition CY MAY 06-10, 2001 CL LONG BEACH, CA SP Soc Advancement Mat & Process Engn DE Hubble Space Telescope; Teflon (R) FEP properties; testing/evaluation AB Following the third servicing mission (SM3A in December '99) to the Hubble Space Telescope, analysis was performed on the two returned panels of multilayer insulation (MIDI) as well as two patches. The NEI panels had been in space since the telescope was launched in April '90 (9.7 years), while the patches were installed during the second servicing mission in February '97 (2.8 years).(1) This paper provides an overview of the tests performed on the returned metallized Teflon FEP along with a summary of results. Testing including determination of mechanical and optical properties, crystallinity and fractography. Because of the amount of material retrieved and the nominal environmental exposures of the retrieved materials, these analyses resulted in a fairly complete understanding of the degradation process affecting the materials on the telescope. Test results from SM3A materials showed significantly better mechanical strength than second servicing mission (SM2) samples. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Blackwood, JR (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-90-5 J9 INT SAMPE TECH CONF PY 2001 VL 46 BP 1797 EP 1810 PG 10 WC Engineering, Chemical; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Materials Science GA BS96V UT WOS:000171526800161 ER PT S AU Dever, JA de Groh, KK Messer, RK McClendon, MW Viens, M Wang, LL Gummow, JD AF Dever, JA de Groh, KK Messer, RK McClendon, MW Viens, M Wang, LL Gummow, JD BE Repecka, L Saremi, FF TI Mechanical properties of Teflon FEP retrieved from the Hubble Space Telescope SO 2001: A MATERIALS AND PROCESSES ODYSSEY, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 46th International SAMPE Symposium and Exhibition CY MAY 06-10, 2001 CL LONG BEACH, CA SP Soc Advancement Mat & Process Engn DE Hubble Space Telescope; Teflon FEP; mechanical properties AB Teflon FEP (fluorinated ethylene propylene) surfaces on the Hubble Space Telescope (HST) have experienced significant degradation in mechanical properties during nearly ten years of exposure in the low Earth orbit (LEO) environment. This paper describes results of mechanical properties testing of Teflon FEP materials exposed on HST for 9.7 years between launch and the third servicing Mission (SM3A) and for 2.8 years between the second servicing mission (SM2) and SM3A. Results of tensile testing, bend testing and microscopic examination of crack morphology are described. Effects of post-retrieval heating and air vs. vacuum storage on the mechanical properties of FEP surfaces are described as they significantly affect interpretation of results regarding the durability of FEP on HST. This paper provides comparisons of the properties of FEP surfaces retrieved during SM3A to previously reported results for FEP materials retrieved during the first servicing mission (SMI) and SM2. Results will be discussed in consideration of the environmental exposure conditions for the HST exposed materials. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Dever, JA (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 8 TC 0 Z9 0 U1 1 U2 2 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-90-5 J9 INT SAMPE TECH CONF PY 2001 VL 46 BP 1811 EP 1825 PG 3 WC Engineering, Chemical; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Materials Science GA BS96V UT WOS:000171526800162 ER PT S AU de Groh, KK Dever, JA Sutter, JK Gaier, JR Gummow, JD Scheiman, DA He, C AF de Groh, KK Dever, JA Sutter, JK Gaier, JR Gummow, JD Scheiman, DA He, C BE Repecka, L Saremi, FF TI Thermal contributions to the degradation of Teflon FEP on the Hubble Space Telescope SO 2001: A MATERIALS AND PROCESSES ODYSSEY, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 46th International SAMPE Symposium and Exhibition CY MAY 06-10, 2001 CL LONG BEACH, CA SP Soc Advancement Mat & Process Engn DE Hubble Space Telescope; Teflon FEP; degradation; embrittlement AB Metallized Teflon((R)) fluorinated ethylene propylene (FEP) thermal control material on the Hubble Space Telescope (HST) is degrading in the space environment. Teflon FEP insulation was retrieved during servicing missions, which occurred in 1993, 1997 and 1999. During the second servicing mission (SM2), the 5 mil aluminized-FEP (Al-FEP) outer layer of mulitlayer insulation (MLI) covering the telescope was found to be cracked in many locations around the telescope. Teflon FEP retrieved during SM2 was more embrittled than FEP retrieved 2.8 years later from a different location, during the third servicing mission (SM3A). Studies have been conducted to understand the degradation of FEP on HST, and the difference in the degree of degradation of FEP from each of the servicing missions. The retrieved SM2 material experienced a higher temperature extreme during thermal cycling (200 degreesC) than first servicing mission (SMI) and SM3A materials (upper temperature of 50 degreesC), therefore an investigation on the effects of heating FEP was also conducted. Samples of pristine FEP and SM1, SM2, and SM3A retrieved FEP were heated to 200 degreesC and evaluated for changes in properties. Heating at 130 degreesC was also conducted because FEP bi-stern thermal shields are expected to cycle to a maximum temperature of 130 degreesC. Tensile, density, x-ray diffraction (XRD) crystallinity and differential scanning calorimetry (DSC) data were evaluated. It was found that heating pristine FEP caused an increase in the density and practically no change in tensile properties. However, when as-retrieved space samples were heated, the density increased and tensile properties decreased. Upon heating, all samples experienced an increase in crystallinity, with larger increases in the space exposed FEP. These results indicate that irradiation of FEP in space causes, chain scission, resulting in embrittlement, and that excessive heating allows increased mobility of space-environment-induced scissioned chains. Thermal exposure was therefore found to have a major impact on the extent of embrittlement of FEP on HST. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP de Groh, KK (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 10 TC 0 Z9 0 U1 1 U2 2 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-90-5 J9 INT SAMPE TECH CONF PY 2001 VL 46 BP 1826 EP 1840 PG 3 WC Engineering, Chemical; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Materials Science GA BS96V UT WOS:000171526800163 ER PT S AU Kim, MHY Thibeault, SA Kiefer, RL Wilson, JW Singleterry, RC Moore, J Huff, H Wilkins, R AF Kim, MHY Thibeault, SA Kiefer, RL Wilson, JW Singleterry, RC Moore, J Huff, H Wilkins, R BE Repecka, L Saremi, FF TI Fabrication and testing of habitat components using in-situ materials for Martian exploration SO 2001: A MATERIALS AND PROCESSES ODYSSEY, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 46th International SAMPE Symposium and Exhibition CY MAY 06-10, 2001 CL LONG BEACH, CA SP Soc Advancement Mat & Process Engn DE human exploration; Mars; Martian; radiation; polyimides; regolith; applications-space AB The development of Mars for human activity will require the utilization of Martian materials in building habitats and working structures. One approach is to use polymer binders with regolith to form structural elements. Not only can useful composite materials be produced in this way but the radiation protection proper-ties are also increased. This is important since only modest protection from space radiation is provided by the Martian atmosphere. We have studied composites fabricated using Martian regolith simulant and polymers which can be synthesized from local Martian materials for their potential use as radiation shields for manned Mars missions. To validate shielding effectiveness, composites are irradiated with a 55 MeV proton beam and neutron beams up to 800 MeV. Shielding effects on microelectronic devices are measured by placing them behind samples of the composites during irradiation. To measure structural properties of the composites, preliminary characterization and mechanical testing are made for the composites. C1 Coll William & Mary, Williamsburg, VA 23187 USA. RP Kim, MHY (reprint author), NASA, LaRC, MS 188B, Hampton, VA 23681 USA. NR 7 TC 0 Z9 0 U1 1 U2 3 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-90-5 J9 INT SAMPE TECH CONF PY 2001 VL 46 BP 1841 EP 1852 PG 8 WC Engineering, Chemical; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Materials Science GA BS96V UT WOS:000171526800164 ER PT S AU Watson, KA Connell, JW Palmieri, FL AF Watson, KA Connell, JW Palmieri, FL BE Repecka, L Saremi, FF TI Space environmentally stable polyimides and copolyimides derived from [2,4-bis(3-aminophenoxy)phenyl]-diphenylphosphine oxide SO 2001: A MATERIALS AND PROCESSES ODYSSEY, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 46th International SAMPE Symposium and Exhibition CY MAY 06-10, 2001 CL LONG BEACH, CA SP Soc Advancement Mat & Process Engn DE low color polyimides; atomic oxygen resistant polymers; phosphine oxide-containing films; polyimides; UV resistant polyimides ID POLY(ARYLENE ETHER HETEROCYCLE)S; OXYGEN PLASMA; FILMS AB Polyimides with a combination of properties including low color in thin films, atomic oxygen (AO), and ultra-violet (UV) radiation resistance, solubility in organic solvents in the imide form, high glass transition (T-g) temperatures and high thermal stability have been prepared and characterized. The polymers were prepared by reacting a novel aromatic diamine, [2,4-bis(3-aminophenoxy)phenyl]-diphenylphosphine oxide (3-APPO), with aromatic dianhydrides in a polar aprotic solvent. The diamine was prepared from commercially available starting materials in a two-step reaction in high yields. Thin films prepared by solution casting of polyimide solutions exhibited very low color and high optical transparency (similar to 80%) as determined by UV/visible spectroscopy. The polymers exhibited T(g)s > 200 degreesC depending upon the structure of the dianhydride. A series of copoly(amide acid)s and copolyimides was prepared using 3-APPO in combination with other aromatic diamines. Based on the chemical structure of these materials it is anticipated that they will have good AO and U-V resistance. They are potentially useful in a variety of applications on spacecraft such as thin film membranes on antennas, second-surface mirrors, thermal/optical coatings and multi-layer thermal insulation (MLI) blanket materials. The chemistry, physical and mechanical properties of the polymers will be discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Watson, KA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 14 TC 4 Z9 4 U1 2 U2 5 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-90-5 J9 INT SAMPE TECH CONF PY 2001 VL 46 BP 1853 EP 1863 PG 3 WC Engineering, Chemical; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Materials Science GA BS96V UT WOS:000171526800165 ER PT S AU Chamis, CC Minnetyan, L AF Chamis, CC Minnetyan, L BE Repecka, L Saremi, FF TI Lube-free composite bearings: Are they viable? SO 2001: A MATERIALS AND PROCESSES ODYSSEY, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 46th International SAMPE Symposium and Exhibition CY MAY 06-10, 2001 CL LONG BEACH, CA SP Soc Advancement Mat & Process Engn DE ball; foil; magnetic AB Research opportunities are described for three rotor-bearing concepts - graphite ball, air-foil and magnetic. Schematics are presented to illustrate conceptual configurations of each; discipline and institutional research opportunities for each. Discipline opportunities include material science, design, analysis, specialty computer code development, testing techniques, fabrication methods and even marketing potential. Institutional include industry, academia and national laboratory. No relevant references are available. However, the descriptive information is provided for the interested researcher to undertake challenging patentable, or copyrighted research relevant to lube-free rotor-bearing technology. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Chamis, CC (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-90-5 J9 INT SAMPE TECH CONF PY 2001 VL 46 BP 1958 EP 1966 PG 3 WC Engineering, Chemical; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Materials Science GA BS96V UT WOS:000171526800174 ER PT S AU Hou, TH Belvin, HL Johnston, NJ AF Hou, TH Belvin, HL Johnston, NJ BE Repecka, L Saremi, FF TI Properties of automated tape placed LARC (TM)-PETI-5 composites SO 2001: A MATERIALS AND PROCESSES ODYSSEY, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 46th International SAMPE Symposium and Exhibition CY MAY 06-10, 2001 CL LONG BEACH, CA SP Soc Advancement Mat & Process Engn DE automated tape placement (ATP); advanced composites; LARC (TM)-PETI-5 AB During NASA's High Speed Research Program, robust autoclave processing cycles for LARC (TM) -PETI-5 composites had been thoroughly designed and demonstrated, These involved band lay-up of solvent-ladened "wet" prepregs. Parallel with this work, heated head robotic tape placement technology was also developed. This technology utilized "dry" material forms and represented a different fabrication process which sought to overcome deficiencies such as volatile management and shrinkage inherent in "wet" prepreg processing. In this work, mechanical properties of composites fabricated by heated bead automated tow placement (dry process) followed by autoclave curing were measured and compared with those obtained by hand lay-up/autoclave fabrication (wet process). First, thermal and theological properties of the robotically as-placed (uncured) IM7/PETI-5 lay-ups were measured. Then, a post-cure cycle was designed to give the PETI-5 resin a required 371 degreesC (700 degreesF)/1-2 hr hold to reach full cure, conditions which cannot be duplicated during heated head robotic placement. Open hole tensile and compressive strength and moduli, 0 degrees flexural strength and modulus, RSC dogbone compressive strength, and MZ-MS tensile and compressive properties were obtained on the cured panels. These properties compared favorably with those obtained from composites made by the wet process. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Hou, TH (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 15 TC 0 Z9 0 U1 1 U2 3 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-90-5 J9 INT SAMPE TECH CONF PY 2001 VL 46 BP 1973 EP 1985 PG 7 WC Engineering, Chemical; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Materials Science GA BS96V UT WOS:000171526800176 ER PT S AU Hulcher, AB Banks, WI Pipes, RB Tiwari, SN Cano, RJ Johnston, NJ AF Hulcher, AB Banks, WI Pipes, RB Tiwari, SN Cano, RJ Johnston, NJ BE Repecka, L Saremi, FF TI Automated fiber placement of PEEK/IM7 composites with film interleaf layers SO 2001: A MATERIALS AND PROCESSES ODYSSEY, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 46th International SAMPE Symposium and Exhibition CY MAY 06-10, 2001 CL LONG BEACH, CA SP Soc Advancement Mat & Process Engn DE thermoplastics; fiber placement; interleaving; barrier films AB The incorporation of thin discrete layers of resin between plies (interleafing) has been shown to improve fatigue and impact properties of structural composite materials. Furthermore, interleafing could be used to increase the barrier properties of composites used as structural materials for cryogenic propellant storage. In this work, robotic heated-head tape placement of PEEK/IM7 composites containing a PEEK polymer film interleaf was investigated. These experiments were carried out at the NASA Langley Research Center automated fiber placement facility.. Using the robotic equipment, an optimal fabrication process was developed for the composite without the interleaf Preliminary interleaf processing trials indicated that a two-stage, process was necessary; the film had to be tacked to the partially-placed laminate then fully melted in a separate operation. Screening experiments determined the relative influence of the various robotic process variables on the peel strength of the film-composite interface. Optimization studies were performed in which peel specimens were fabricated at various compaction loads and roller temperatures at each of three film melt processing rates. The resulting data were fitted with quadratic response surfaces. Additional specimens were fabricated at placement parameters predicted by the response surface models to yield high peel strength in an attempt to gage the accuracy of the predicted response and assess the repeatability of the process. The overall results indicate that quality PEEK/IM7 laminates having film interleaves can be successfully and repeatability fabricated by heated head automated fiber placement [1]. C1 Old Dominion Univ, Norfolk, VA USA. RP Hulcher, AB (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 10 TC 1 Z9 1 U1 0 U2 3 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-90-5 J9 INT SAMPE TECH CONF PY 2001 VL 46 BP 1998 EP 2012 PG 7 WC Engineering, Chemical; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Materials Science GA BS96V UT WOS:000171526800178 ER PT S AU Cano, RJ Belvin, HL Johnston, NJ Hulcher, AB Marchello, JM Grenoble, RW Wilenski, MS Burgess, JW AF Cano, RJ Belvin, HL Johnston, NJ Hulcher, AB Marchello, JM Grenoble, RW Wilenski, MS Burgess, JW BE Repecka, L Saremi, FF TI A prototype research laboratory for automated fabrication of high performance composites SO 2001: A MATERIALS AND PROCESSES ODYSSEY, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 46th International SAMPE Symposium and Exhibition CY MAY 06-10, 2001 CL LONG BEACH, CA SP Soc Advancement Mat & Process Engn DE automated tape placement; composite materials; fabrication/processing ID PLACEMENT AB A new NASA fiber placement facility has proven to be a valuable asset for obtaining data, experience, and insights into the automated fabrication of high performance composites. The facility consists of two automated devices: an ABB robot armed with a modified heated head capable of hot gas and focused infrared heating and a 7' x 17' gantry containing a feeder head, rotating platform, focused infrared lamp and e-beam gun. While uncured thermoset tow and tape, e.g., epoxy and cyanate prepreg, can be placed with the ABB robot, its most powerful attribute is the ability to place thermoplastic material to net shape. In recent years, ribbonizing techniques have been developed to make high quality thermoplastic and thermoset dry material forms to the standards required for robotic placement. A variety of composites have been fabricated from these ribbons by heated head tow and tape placement including both flat plates and cylinders. Property values of the former were between 85 and 100 percent of those obtained by hand lay-up/autoclave processing. The relatively small but compact gantry was built for NASA by Boeing and is a recent addition to the NASA Langley laboratory capability. It has full computer control and been used to fabricate e-beam-cured composites using in situ (ply-by-ply, cure-on-the-fly) processing. Future work is directed toward screening new materials and tailoring these two automated devices to develop processes to fabricate net shape composites by non-autoclave techniques. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Cano, RJ (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 10 TC 0 Z9 0 U1 0 U2 1 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-90-5 J9 INT SAMPE TECH CONF PY 2001 VL 46 BP 2037 EP 2047 PG 5 WC Engineering, Chemical; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Materials Science GA BS96V UT WOS:000171526800181 ER PT B AU Hillard, GB Kirkici, H AF Hillard, GB Kirkici, H GP IEEE IEEE TI High Voltage Design Guidelines: A timely update SO 2001 ANNUAL REPORT CONFERENCE ON ELECTRICAL INSULATION AND DIELECTRIC PHENOMENA LA English DT Proceedings Paper CT Annual Conference on Electrical Insulation and Dielectric Phenomena (CEIDP) CY OCT 14-17, 2001 CL WATERLOO, CANADA SP IEEE Dielect & Elect Insulat Soc AB The evolving state of high voltage systems and their increasing use in the space program have called for a revision of the high Voltage Design Guidelines, Marshall Space Flight Center technical document MSFC-STD-531, originally issued September 1978 (previously 50 M05189b, October 1972). These guidelines deal in depth with issues relating to the specifying of materials, particularly electrical insulation, as well as design practices and test methods. Emphasis is on corona and Paschen breakdown as well as plasma effects for Low Earth Orbiting systems. We will briefly review the history of these guidelines as well as their immediate predecessors and discuss their range of applicability. In addition, this document has served as the basis for several derived works that became focused, program-specific HV guidelines. We will briefly review two examples, guidelines prepared for the X-33 program and for the Space Shuttle Electric Auxiliary Power Unit (EAPU) upgrade. C1 NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Hillard, GB (reprint author), NASA, John H Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7053-8 PY 2001 BP 409 EP 411 DI 10.1109/CEIDP.2001.963569 PG 3 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Fluids & Plasmas; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BT18U UT WOS:000172225000094 ER PT B AU Hass, KJ Venbrux, J Bhatia, P AF Hass, KJ Venbrux, J Bhatia, P BE Brunvand, E Myers, C TI Logic design considerations for 0.5-volt CMOS SO 2001 CONFERENCE ON ADVANCED RESEARCH IN VLSI, PROCEEDINGS LA English DT Proceedings Paper CT Conference on Advanced Research in VLSI (ARVLSI 2001) CY MAR 14-16, 2001 CL UNIV UTAH, SALT LAKE CITY, UT SP IEEE Electron Devices Soc HO UNIV UTAH ID LOW-POWER AB As the operating supply voltage for commercial CMOS devices falls below 2 V, research activities are underway To develop CMOS integrated circuits that can operate at supply voltages well under 1 V. Although dramatic power reductions can be achieved using low supply voltages in high performance applications. the increased subthreshold leakage that results rr hen transistor threshold voltages are lowered can render some conventional logic circuit styles unusable. Furthermore, some low voltage circuits are not robust when faced with normal variations in threshold voltage. This paper examines the design considerations for logic and memory circuits in very low voltage CMOS, and compares simulated behavior with measurements of fabricated test circuits. These circuit examples were chosen because they illustrate the unique design challenges of low voltage CMOS. C1 Univ New Mexico, NASA, Inst Adv Microelect, Albuquerque, NM 87131 USA. RP Hass, KJ (reprint author), Univ New Mexico, NASA, Inst Adv Microelect, Albuquerque, NM 87131 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1038-8 PY 2001 BP 75 EP 85 DI 10.1109/ARVLSI.2001.915552 PG 11 WC Engineering, Electrical & Electronic SC Engineering GA BS44R UT WOS:000169874500006 ER PT S AU Sterling, T AF Sterling, T GP IEEE IEEE TI Petaflops computing: Status and prospects SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Sterling, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 7 EP 7 PG 1 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700002 ER PT S AU Randolph, J Eremenko, A Miyake, R Dirling, R AF Randolph, J Eremenko, A Miyake, R Dirling, R GP IEEE IEEE TI To fly to the sun: The mission and technology challenges of the solar probe SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB To fly close to the sun (to a perihelion of 4 solar radii) represents many unique challenges to a mission and spacecraft design. The Solar Probe design is a result of over two decades of studies that have allowed the evolution of both the mission and trajectory design, as well as the spacecraft configurations. During these studies some of the most significant design challenges have been the trajectory design, the spacecraft shield design, the spacecraft configuration, the telecommunications near perihelion, science instrument accommodations, and minimizing the cost of the mission. This latter challenge (minimum cost) permeates all of the other design issues suggesting specific solutions consistent with this constraint. This paper will present the evolution and rationale that has taken place to arrive at the current design for this challenging mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Randolph, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 51 EP 62 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700008 ER PT S AU White, AL AF White, AL GP IEEE IEEE TI Establishing ultra-reliability by fault injection experiments SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB A validation procedure combines field data, arguments-from-design, and fault injection experiments to demonstrate high reliability. This paper covers integrating these elements and deriving results that reduce the fault injection effort. A typical argument about the impossibility of demonstrating ultra reliability by experiment is presented to motivate the emphasis on reducing the experimental effort. An example is used to explain the integration of field data, fault injection, arguments-from-design, and performance monitoring. This validation procedure has stringent requirements, but it is shown that these requirements are common to other procedures. There is an extended analysis on number, type, and time of fault occurrence. These results are applied to a system with an extremely high reliability requirement. They reduce the experimental effort to a moderate level. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP White, AL (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 103 EP 114 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700012 ER PT S AU Volpe, R Nesnas, I Estlin, T Mutz, D Petras, R Das, H AF Volpe, R Nesnas, I Estlin, T Mutz, D Petras, R Das, H GP IEEE IEEE TI The CLARAty architecture for robotic autonomy SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID MARS ROVER; SYSTEM AB This paper presents an overview of a newly developed Coupled Layer Architecture for Robotic Autonomy (CLARAty), which is designed for improving the modularity of system software while more tightly coupling the interaction of autonomy and controls. First, we frame the problem by briefly reviewing previous work in the field and describing the impediments and constraints that been encountered. Then we describe why a fresh approach of the topic is warranted, and introduce our new two-tiered design as an evolutionary modification of the conventional three-level robotics architecture. The new design features a tight coupling of the planner and executive in one Decision Layer, which interacts with a separate Functional Layer at all levels of system granularity. The Functional Layer is an object-oriented software hierarchy that provides basic capabilities of system operation, resource prediction, state estimation, and status reporting. The Decision Layer utilizes these capabilities of the Functional Layer to achieve goals by expanding, ordering, initiating and terminating activities. Both declarative and procedural planning methods are used in this process. Current efforts are targeted at implementing an initial version of this architecture on our research Mars rover platforms, Rocky 7 and 8. In addition, we are working with the NASA robotics and autonomy communities to expand the scope and participation in this architecture, moving toward a Right implementation in the 2007 time-frame. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Volpe, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 41 TC 11 Z9 11 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 121 EP 132 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700014 ER PT S AU Barrett, A Rabideau, G Estlin, T Chien, S AF Barrett, A Rabideau, G Estlin, T Chien, S GP IEEE IEEE TI Coordinated continual planning methods for cooperating rovers SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB This paper uses eight evaluation metrics to compare and contrast three coordination schemes for a system that continuously plans to control collections of rovers (or spacecraft) using collective mission goals instead of goals or command sequences for each spacecraft. These schemes use a central coordinator to either (1) micromanage rovers one activity at a time, (2) assign mission goals to rovers, or (3) arbitrate mission goal auctions among rovers. A self-commanding collection of rovers would autonomously coordinate itself to satisfy high-level science and engineering goals in a changing partially understood environment - making the operation of tens or even a hundred spacecraft feasible. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Barrett, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 126-347, Pasadena, CA 91109 USA. NR 17 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 133 EP 140 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700015 ER PT S AU Knight, R Chien, S Keller, R AF Knight, R Chien, S Keller, R GP IEEE IEEE TI Enabling onboard spacecraft autonomy though goal-based architectures: an integration of model-based artificial intelligence planning with procedural elaboration SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB This paper describes the integration of a model-based planner into a procedural architecture. This architecture is unusual in that the internal procedures and the planners inter-operate in an asynchronous fashion in a multithreaded environment via a goal-based interface. The submission of goals may trigger either internal procedures or planners, and both internal procedures and planners may submit goals. The procedural architecture described is the Mission Data System (MDS) Goal Achieving Module (GAM) architecture. The planner described is the CASPER (Continuous Activity Scheduling Planning Execution and Replanning) system. This approach has been prototyped and tested against virtual spacecraft and comet-lander operations scenarios and simulations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Knight, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 24 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 141 EP 149 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700016 ER PT S AU Smith, BD Engelhardt, BE Mutz, DH Crawford, JP AF Smith, BD Engelhardt, BE Mutz, DH Crawford, JP GP IEEE IEEE TI Automated planning for the modified antarctic mapping mission SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The RadarSAT Modified Antarctic Mapping Mission (MAMM) ran from September to November 2000. The MAMM mission consisted of over 2400 synthetic aperture radar (SAR) data takes over Antarctica that had to satisfy coverage and other scientific criteria while obeying tight resource and operational constraints. Developing these plans is a time and knowledge intensive effort. It required over a work-year to manually develop a comparable plan for AMM-1, the precursor mission to MAMM. This paper describes the automated mission planning system for MAMM, which dramatically reduced mission planning costs to just a few work-weeks, and enabled rapid generation of "what-if" scenarios for evaluating mission-design trades. This latter capability informed several critical design decisions and was instrumental in accurately costing the mission. This paper describes the mission, the planning problem, the system architecture, the planning challenges involved, and the impact of the automated planning system on planning and operating the mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Smith, BD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 126-347, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 151 EP 158 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700017 ER PT S AU Kerzhanovich, VV Hall, JL Yavrouian, A AF Kerzhanovich, VV Hall, JL Yavrouian, A GP IEEE IEEE TI Balloon precursor mission for venus surface sample return SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB This paper proposes a Precursor mission to the Venus Surface Sample return Mission (VSSR). The present scenario of the VSSR [1] includes delivery by a balloon of the Venus Ascent Vehicle (VAV) from the surface to an altitude of approximately 60 km, where it can be launched without huge penalty for atmospheric losses. The mission includes a number of critical technologies that can be validated in this proposed precursor mission. The other objective of the proposed mission is to collect the more accurate data on Venus atmosphere that is essential for the VSSR mission design. The precursor mission would consist of an entry vehicle carrying two probes. The entry vehicle would be inserted in the Venus atmosphere from an approach trajectory. One probe would include a zero-pressure balloon that will deploy and inflate at an altitude 55 km and rise to 80 km. During this ascent it would collect data on vertical structure, wind and turbulence that are essential for the VAV guidance and control. These data would also provide the first high-resolution data collected for this region of the atmosphere. The data will be transmitted directly to the DSN station. The second probe would be a sub-scale prototype of the VSSR lander and will include the VAV simulator, the high-temperature balloon, inflation and thermal control systems. During the descent it would provide high-accuracy temperature and pressure measurements of the atmosphere (there is no accurate data on the vertical structure of the lowest 12 km where the Pioneer Venus sensors ceased to operate and the VEGA 2 lander pressure sensor did not have adequate accuracy). The balloon would be inflated and released to ascend to the nominal VAV launch altitude of 60 km. Atmospheric and balloon performance data will be transmitted directly to Earth. This probe would validate the technologies that are most critical for the VSSR. As a descope option, the high-temperature balloon could be deployed and inflated at 50-55 km and then allowed to descend to the surface. In this case only balloon technology would be validated. The paper will discuss the basic mission and system elements for the proposed precursor mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kerzhanovich, VV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 163 EP 170 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700019 ER PT S AU Erickson, KD Kelleher, KD Kenny, JT Wigglesworth, LD AF Erickson, KD Kelleher, KD Kenny, JT Wigglesworth, LD GP IEEE IEEE TI STRV-2 payload early orbit experience and findings SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The STRV-2 (Space Technology Research Vehicle) Experiment Module (EM), was launched June 7, 2000 on a Pegasus XL launcher out of Vandenberg Air Force Base. STRV-2 is the primary payload on this Tri-Service Experiment Mission 5 (TSX-5), which is the sixth mission for the Air Force Space Test Program (STP). The EM is an integrated collection of eleven active Experiments and one passive. The active Experiments are commanded and controlled by the STRV-2 System Control Module (SCM) over a 1553 bus. The SCM is also the data interface to the spacecraft's command, communications, and data handling processors. The active Experiments include high data rate optical communications, infrared imaging of aircraft and ships, vibration isolation and suppression, micrometeoroid impact detection. active pixel sensor imaging, micro-g accelerometers, contamination transport mechanisms, advanced solar photovoltaic systems, thermal control materials, and radiation monitors on a chip. The TSX-5 orbit is a 410-km by 1710-km elliptical orbit, which takes STRV-2 into the Mid-Earth Orbit (MEO) region of space. STRV-2 is the first to study the micrometeoroid and debris population at these altitudes. Nine Principal Investigators (PIs) are associated with the active Experiments. The Jet Propulsion Laboratory (JPL) is coordinating with the PIs to establish weekly operation timelines for all Experiments; each competing for limited spacecraft resources. This paper describes the processes for developing deconflicted operation schedules, for developing the operation files, which are loaded to the SCM to command and operate the individual Experiments, and for processing, distributing, and reporting Experiment operation results. Eight to ten space ground link sessions are required daily to upload and download STRV-2 command and data files. Experiment results will be described for the first seven months of mission operations, as will the plans for the last few months of this one-year mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Erickson, KD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 171 EP 179 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700020 ER PT S AU Kenny, JT Pollock, HR AF Kenny, JT Pollock, HR GP IEEE IEEE TI STRV-1d QWIP technology validation in space flight SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB New technologies are arriving on the scene that promise enhancement or new capabilities. Some of these technologies have potential for NASA and DOD space-based applications. In these cases. the technology must be demonstrated and validated to a degree that risk may be balanced for the space mission roles. Quantum Well Infrared Photodetector (QWIP) is one of these technologies. QWIP has a variety of space-based applications in the 8 to 16 mum wavelength range. Radiation tolerance and higher operating temperature are potentially significant benefits for long duration missions. In this paper, we describe the selection of and preparation for a mission that provides the opportunity to demonstrate and validate QWIP FPA in the natural, space radiation environment. We discuss the objectives of this demonstration opportunity, and the development and test steps required to deliver the QWIP Experiment to space. C1 CALTECH, Jet Prop Lab, Space Instruments Implementat Sect, Pasadena, CA 91109 USA. RP Kenny, JT (reprint author), CALTECH, Jet Prop Lab, Space Instruments Implementat Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 181 EP 186 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700021 ER PT S AU LaBel, KA Barth, JL Brewer, D Kaufmann, B Howard, R Giffin, G Marshall, C Marshall, P AF LaBel, KA Barth, JL Brewer, D Kaufmann, B Howard, R Giffin, G Marshall, C Marshall, P GP IEEE IEEE TI The effects of solar variability on technology: Objectives of NASA's space environment testbed SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID SATELLITE DATA MANAGEMENT; OPTIC DATA LINKS; RADIATION; MODEL AB The Space Environment Testbed (SET) is a complementary element of NASA's new Living With a Star (LWS) Program. This program is designed to help humankind understand and successfully exist with the sun and its variability throughout the solar cycle. The SET element is a series of flight testbeds focused on this variability and its effects on space system technology, as well as crew safety. In particular, the SET aims to improve the engineering approach and/or mitigate the effects of solar variability on spacecraft design and operations. The SET encompasses a series of flight testbeds with collateral environment measurements. The SET supports incorporation of the results from experiments and environment measurements (both on SET flight testbeds and elsewhere) into improved application models. This program is an FYO1 new initiative. C1 NASA, GSFC, Radiat Effects 7 Anal Grp, Washington, DC 20546 USA. RP LaBel, KA (reprint author), NASA, GSFC, Radiat Effects 7 Anal Grp, Washington, DC 20546 USA. NR 27 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 199 EP 208 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700023 ER PT S AU Cutts, JA Kerzhanovich, VV AF Cutts, JA Kerzhanovich, VV GP IEEE IEEE TI Martian aerobot missions: First two generations SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The possible role of aerobot missions as new vehicles for Mars exploration has been emphasized at the recent NASA Workshop on Concepts and Approaches for Mars Exploration (Houston, July 2000). The unique combination of proximity to the surface, and mobility exceeding tens of thousands of kilometers complements the capabilities of orbital platforms and surface rovers. C1 CALTECH, Jet Prop Lab, Mars Explorat Off, Pasadena, CA 91109 USA. RP Cutts, JA (reprint author), CALTECH, Jet Prop Lab, Mars Explorat Off, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 235 EP 242 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700026 ER PT S AU Graf, J Thurman, S Eisen, H Rivellini, T Sabahi, D AF Graf, J Thurman, S Eisen, H Rivellini, T Sabahi, D GP IEEE IEEE TI Second generation Mars landed missions SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Mars future landed missions include safe, accurate landing of payloads large enough to accomplish a sample return mission or to accommodate both a comprehensive science instrument suite and extensive in situ resource utilization payloads. In addition. the landers may be fixed (immovable) or have sufficient mobility capability to rove multiple kilometers on the surface. Accurate landing. coupled with extensive roving capability that exceeds landing error ellipses. enable "Go to" missions in which a specific, selected feature (e.g., seepage site) on the surface can be investigated with a major payload complement. This paper addresses some of the candidate missions being considered for the next-generation projects, discusses the new approaches being developed to implement safe and accurate entry, descent and landing (EDL) to the Martian surface, and describes the rover technology that enables the long distance and duration surface mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Graf, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 264-440, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 243 EP 254 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700027 ER PT S AU Feldman, JE Wilcox, JZ George, T Bridges, N AF Feldman, JE Wilcox, JZ George, T Bridges, N GP IEEE IEEE TI Atmospheric electron x-ray spectrometer development SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The development of a portable surface elemental analysis tool based on the excitation of characteristic x-rays at ambient pressure with an electron beam is described. This instrument relies on the use of a thin electron transmissive membrane to isolate the vacuum of the electron source from the ambient atmosphere. The major advantages offered by this instrument include rapid spectrum acquisition. non-destructive evaluation of elemental composition, and high spatial resolution in comparison to similar portable instruments. The instrument proof-of-principle has been demonstrated by obtaining energy dispersive x-ray spectra from metal and mineral samples. Scanning Electron Microscope (SEM) experiments have been carried out to determine beam spot size and quantitative analysis limits. Modeling has been performed to study performance limits and to understand the influence of membrane and atmosphere interactions on the focused electron beam. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Feldman, JE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 255 EP 261 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700028 ER PT S AU Bar-Cohen, Y Sherrit, S Dolgin, BP Bridges, N Bao, XQ Chang, ZS Yen, A Saunders, RS Pal, D Kroh, J Peterson, T AF Bar-Cohen, Y Sherrit, S Dolgin, BP Bridges, N Bao, XQ Chang, ZS Yen, A Saunders, RS Pal, D Kroh, J Peterson, T GP IEEE IEEE TI Ultrasonic/sonic driller/corer (USDC) as a sampler for planetary exploration SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Future NASA exploration missions to Mars. Europa, Titan. comets, and asteroids will perform sampling, in-situ analysis and possibly the return of material to Earth for further tests. One of the major limitations of sampling in low gravity environments is that conventional drills need high axial force. An ultrasonic/sonic driller/corer (USDC) mechanism was developed to address these and other limitations of existing drilling techniques. The USDC is based on an ultrasonic horn that is driven by a piezoelectric stack. The horn drives a free-mass, which resonates, between the horn and drill stem. Tests have shown that this device addresses some of the key challenges to the NASA objective of planetary in-situ sampling and analysis. The USDC is lightweight (450 g), requires low pre-load (< 5N) and can be driven at low power (5W). The device was operated from such robotic platforms as the Sojourner rover and the FIDO robotic arm and it has been shown to drill various rocks including granite, diorite, basalt and limestone. The drill can potentially operate at high and low temperatures and does not require sharpening. Although the drill is driven electrically at 20 kHz. a substantial subharmonic acoustic component is found that is crucial to drilling performance. Models that explain this low frequency coupling in the horn, free-mass, drill stem and rock are presented. Efforts are currently underway to integrate the models and experimentally corroborate the predictions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 82-105, Pasadena, CA 91109 USA. NR 3 TC 2 Z9 2 U1 2 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 263 EP 271 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700029 ER PT S AU George, T Chang-Chien, A Madsen, L Leskowitz, G Tang, WL Weitekamp, D AF George, T Chang-Chien, A Madsen, L Leskowitz, G Tang, WL Weitekamp, D GP IEEE IEEE TI MEMS-based force-detected nuclear magnetic resonance spectrometer for in situ planetary exploration SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Nuclear magnetic resonance (NMR) is the most widely used spectroscopic technique for characterization of molecular structures and reactions. NMR is especially powerful in detecting the presence of water and distinguishing between arbitrary physisorbed and chemisorbed states. This ability is particularly important in the search for extra-terrestrial life on planets such as Mars, where there are strong indications that liquid water exists or has existed previously. Conventional NAM technology based on magnetic induction is unsuitable for remote applications because these instruments are heavy and require excessive power. We recently demonstrated a new NMR technology based on magnetic force detection that is suitable for NMR analysis in remote environments and on small samples [2,3]. This paper details our efforts toward realizing this technology on small scales using a MEMS (micro electro mechanical systems) approach. Applications of this new MEMS-based NMR method to planetary exploration are discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP George, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 302-306, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 273 EP 278 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700030 ER PT S AU Kossakovski, DA Bearman, GH Kirschvink, JL AF Kossakovski, DA Bearman, GH Kirschvink, JL GP IEEE IEEE TI In-situ chemical imager SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID BREAKDOWN AB A variety of in-situ planetary exploration tasks such as particulate analysis or life detection require a tool with a capability for combined imaging and chemical analysis with sub-micron spatial resolution. In our instrument, spatially resolved chemical imaging is achieved by augmenting a fiber optic scanning probe microscope with laser induced break-down spectroscopy. Elemental composition of surfaces can be mapped and correlated with topographical data. Experiments are conducted in ambient conditions or under vacuum with minimal sample preparation. A sharp fiber optic probe is used as a means for topographical analysis and as a delivery tool for pulsed laser radiation that vaporizes material below the probe. Optical emission from the ablation plume is analyzed with a UV/VIS spectrometer equipped with an intensified CCD detector. The ablation crater size is controlled by the amount of laser power coupled into the probe. Sampling areas with submicron dimensions are achieved by using reduced laser power. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kossakovski, DA (reprint author), CALTECH, Jet Prop Lab, MS 306-336,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 279 EP 284 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700031 ER PT S AU Dolgin, B Bickler, D Carson, J Chung, S Quicksall, J Troy, R Yarbrough, C AF Dolgin, B Bickler, D Carson, J Chung, S Quicksall, J Troy, R Yarbrough, C GP IEEE IEEE TI Earth contamination free sample acquisition from an earth contaminated spacecraft SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The paper describes the first step in the feasibility demonstration of a novel low cost Mars Sample Return Sample Transfer Sequence (STS) that does not require cleaning and sterilization of the entire spacecraft. The proposed STS relies on ability to collect (and in the future deliver to Earth) Earth-contamination-free samples from a spacecraft that was cleaned only to the levels achieved on Pathfinder. The latter satisfied Planetary Protection Category IVa (PP IVa) requirements, typical for a landed spacecraft. Ability to sterilize or clean to sterility the entire spacecraft is a risky and poorly developed technology. The proposed sample collection approach relies on mechanical removal of the contaminated surface layer and collection of a clean sample from the cleared area. Verification procedures for this approach require probabilistic assessments of the sample contamination levels for a given level of surface contamination. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dolgin, B (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 285 EP 289 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700032 ER PT S AU Bearman, GH Kossakovski, DA AF Bearman, GH Kossakovski, DA GP IEEE IEEE TI ISHMAEL: In-situ sample handling modular analytical experimental laboratory SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID SPECTROSCOPY; FLOW AB In-Situ instruments are an integral part of mission designs for exploration of planetary surfaces. A technology gap exists today between sample acquisition and sample analysis tools. Integrated science payload packages need an integrated sample handling system. One approach is to transport and manipulate samples from a few microns up to similar to 100 microns in diameter by a carrier fluid contained in microfluidic manifold of channels. We are developing a set of modular, reconfigurable, rapid prototyping components for sample manipulation. This set will consist of passive and active components. The passive components are easily stackable in three dimensions and can be built into complex distribution geometries to service many instruments. The active components will allow for sample sorting, gating and immobilization. We will use dielectrophoretic technology to manipulate particles in liquid flow. In addition to simply handling the sample we can also perform certain science tasks. such as dielectric spectroscopy or microscopic analysis of caged particles. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bearman, GH (reprint author), CALTECH, Jet Prop Lab, MS 306 336,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 291 EP 298 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700033 ER PT S AU Van Steenberg, ME Washabaugh, A Goldfine, N AF Van Steenberg, ME Washabaugh, A Goldfine, N GP IEEE IEEE TI Inductive and capacitive sensor arrays for in situ composition sensors SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Advances in electromagnetic sensor design provide the potential for high resolution imaging of subsurface objects and material properties at the microscopic (micrometer) and mesoscopic (meter) scales. With quasi-static., capacitive and inductive sensor arrays, objects are detected, identified, and imaged via their perturbations to the applied electric and magnetic fields, rather than through time delays of reflected electromagnetic waves as in ground penetrating radar. Building on the successful application as nondestructive quality assessment and monitoring tools as well as land mine detectors, several sub-surface in situ sensors are enabled by this technology. Examples include: an electronic 3D microscope, enabling examination of cell level structures and composition; examination of near surface structures such as, soil moisture, permafrost dynamics, soil properties with depth, root growth carbon sequestration, Martian surface aquifers, and buried deposits of carbon dioxide or methyl hydrides. C1 NASA, Goddard Space Flight Ctr, Astrophys Data Facil, Greenbelt, MD 20771 USA. RP Van Steenberg, ME (reprint author), NASA, Goddard Space Flight Ctr, Astrophys Data Facil, Code 631, Greenbelt, MD 20771 USA. NR 15 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 299 EP 309 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700034 ER PT S AU Zimmerman, W Bonitz, R Feldman, J AF Zimmerman, W Bonitz, R Feldman, J GP IEEE IEEE TI Cryobot: An ice penetrating robotic vehicle for Mars and Europa SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB NASA's desire to study and characterize the solar system will be done by in-situ robotic systems in the near term. Specific interest is focused towards finding water on Mars and understanding both the climatic and depositional history of the planet. In the case of Europa, scientists desire to unravel the mysteries surrounding the thick ice crust. its chemical properties, and subsurface ocean properties. For both Mars and Europa. the major scientific interest is whether there are signs of past or extant life in either the Mars polar ice, or the sub-ice ocean of Europa. The best way to explore either of these environments is a cryobot mole vehicle, which carries a suite of instruments suitable for sampling and analyzing the ice or ocean environments. JPL is currently developing a unique robotic vehicle, which utilizes gravity, and both passive and active heating systems to drive ice to a melt state, in order to facilitate mobility. This paper describes the science driven requirements for such a vehicle, a description of the cryobot design, and results of recent performance tests in both clean and dust laden ice. Although a radioisotope power system for a flight version of the cryobot is currently baselined, no decision on the final design of the flight cryobot will be made until the environmental review process is complete. Any use of the cryobot for Mars or Europa will conform to all environmental and planetary protection requirements. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zimmerman, W (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 3 Z9 3 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 311 EP 323 PG 13 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700035 ER PT S AU Behar, A Carsey, F Lane, A Engelhardt, H AF Behar, A Carsey, F Lane, A Engelhardt, H GP IEEE IEEE TI The Antarctic Ice Borehole Probe SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Antarctic Ice Borehole Probe mission is a glaciological investigation, scheduled for November 2000-January 2001, that will acquire visible-light images and video in a hot-water drilled hole in the West Antarctic ice sheet, The objectives of the probe are to observe ice-bed interactions with a downward looking camera, and ice inclusions and structure. including hypothesized ice accretion. with a side-looking camera. The Probe mission also serves as a stepping-stone in the development of technology to acquire data in extreme ice and liquid environments. The information and experience will aid projects involving exploration in ice/liquid environments, including missions to Lake Vostok in Antarctica, Mars Polar Caps and Europa. Jupiter's moon. This focus of this paper is to describe the design and use of the probe. C1 CALTECH, Jet Prop Lab, Avion Syst & Technol Div, Pasadena, CA 91109 USA. RP Behar, A (reprint author), CALTECH, Jet Prop Lab, Avion Syst & Technol Div, 107-102, Pasadena, CA 91109 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 325 EP 330 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700036 ER PT S AU Buehler, MG Kounaves, SP Martin, DP West, SJ Kuhlman, GM AF Buehler, MG Kounaves, SP Martin, DP West, SJ Kuhlman, GM GP IEEE IEEE TI Designing a water-quality monitor with ion selective electrodes SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB This effort is directed at developing a sensor for evaluating water quality. A set of nine ion selective electrodes (ISEs) are being fabricated on a 4.5-cm diameter ceramic substrate. This paper discusses the design and fabrication of the deposition chamber and the ceramic substrates that form the basis for the ISEs. The chamber, substrate and electronics design was validated to assure that the multiplexing electronics functions, the ceramic substrate mounted is stress-free, and the deposition chamber is water tight. Results from the electrolysis of a dilute nitric acid solution are presented to further validate the design concept. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Buehler, MG (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 3 TC 2 Z9 3 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 331 EP 339 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700037 ER PT S AU Calabrese, MA AF Calabrese, MA GP IEEE IEEE TI NASA Sun-Earth Connection program strategic mission & technology requirements (2006-2015) SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Our variable star, the Sun, is the source of varying solar wind, electromagnetic radiation and electromagnetic particles that interact with the Planets and the Galaxy. The Sun-Earth Connection (SEC) Theme in the NASA Office of Space Science (OSS) has a strategic goal to understand our changing Sun and its effects on the Solar System, Life and Society. The SEC Roadmap defines the major science questions or Quests from which a series of strategic roadmap missions are identified to provide the measurements to address these quests. The SEC Roadmap strategy is to develop a series of modest, synergistic missions integrated with a few more capable break-through missions. Together, these missions will allow us to discover and understand the connected Sun-Earth system in the spatial, temporal, and spectral domain from widely distributed vantage points in space. These strategic missions are being pursued in three general flight program areas including Solar Terrestrial Probes, A Space Weather Research Network in the new Living With a Star Program, and through Frontier Probes. These missions build on the International Solar Terrestrial Physics Program (ISTP) and SEC missions in the 1990's and early 2000's where the importance of system understanding of the variable Sun and interaction with the Earth's geospace was identified. This paper describes the planned SEC strategic missions planned for the period 2006-2015 and their technology requirements. These missions range from individual spacecraft to clusters and constellations of micro-nano satellite missions utilizing both imaging and in-situ instrumentation. Enabling technologies include micro-nano satellite and instrumentation along with solar sail propulsion providing reduced flight times and unique non-keplerian orbits to extend traditional vantage points. Enhancing technology requirements related to instruments and subsystems are described that will improve payload mass-fraction, improved performance and lower cost. C1 NASA, Goddard Space Flight Ctr, Off Assocaite Director, Greenbelt, MD 20771 USA. RP Calabrese, MA (reprint author), NASA, Goddard Space Flight Ctr, Off Assocaite Director, Code 101, Greenbelt, MD 20771 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 373 EP 382 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700042 ER PT S AU Wanjek, C White, N Horowitz, S AF Wanjek, C White, N Horowitz, S GP IEEE IEEE TI NASA's cosmic journeys missions: A quest for the nature of gravity SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Cosmic Journeys is a new series of NASA space science missions housed within the Structure and Evolution of the Universe science theme. The central goal of the Cosmic Journeys missions is to solve the mystery of gravity, a fundamental force that is all around us but about which very little is known. Cosmic Journeys will use the power of resolution far greater than what current telescopes can muster to virtually transport us to regions in space and time where gravity is most compelling: at the rim of a black hole, across galaxy clusters and voids that pervade the Universe, and at the moment after the Big Bang when the four fundamental forces may have been intertwined. Cosmic Journeys will have a fleet of orbiting observatories at its command capturing the full range of the electromagnetic spectrum. The NASA Journeys program is also forging a partnership with the National Science Foundation (NSF) and the Department of Energy (DOE), called "Connections: From Quarks to the Cosmos," with hopes of bringing together physicists, astronomers and other professionals who have traditionally worked independently. Together, the three agencies will fund a variety of ground- and space-based research. C1 NASA, Goddard Space Flight Ctr, SP Syst Inc, Greenbelt, MD 20771 USA. RP Wanjek, C (reprint author), NASA, Goddard Space Flight Ctr, SP Syst Inc, Code 662, Greenbelt, MD 20771 USA. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 383 EP 388 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700043 ER PT S AU Nilsen, E Weissman, P AF Nilsen, E Weissman, P GP IEEE IEEE TI Odyssey - A comet nucleus orbiter SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Odyssey (not to be confused with the recently named Mars '01 orbiter) is an exciting comet nucleus orbiter mission submitted to the Discovery 2000 Announcement of Opportunity [1]. This mission will rendezvous with and orbit a comet nucleus, and will make detailed scientific measurements with unprecedented resolution and accuracy. It is widely recognized that the best obtainable clues to the origin of the solar system can be found in its small bodies, comets and asteroids. Only in these small, relatively unprocessed bodies is the cosmo-chemical and physical record of the early solar system preserved. Unprocessed volatiles can be found in only one place: in cometary nuclei. Odyssey will address elements of all three quests enumerated in the Solar System Exploration Strategic Plan. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nilsen, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 301-170U, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 397 EP 402 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700045 ER PT S AU Oberto, R AF Oberto, R GP IEEE IEEE TI The challenge of landing on Europa SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Europa is one of the most scientifically interesting objects in the solar system because of the strong possibility that a liquid water ocean exists beneath its ice-covered surface. The primary scientific goals of the mission are to confirm the existence of a liquid ocean, characterize surface material from recent upwelling and took for evidence of pre-biotic chemistry. The mission concept involves landing a single spacecraft on the surface of Europa with the ability to collect samples from 10 centimeters below the surface, perform analysis of the samples, and transmit the results back to Earth. Because of the large DeltaV required (4.3 km/sec), the propellant mass comprises 70% of the spacecraft wet mass. This large DeltaV requirement is further exasperated by the radiation shielding mass needed to protect the avionics and instruments from Jupiter's severe radiation environment (7.5 Mrad behind 40 mils A1). The spacecraft will require radiation-tolerant components; new devices for acquiring, distributing, and processing samples; an advanced RTG power source, and a capability to perform autonomous precision navigation leading to a safe landing on Europa's uncharacterized surface. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Oberto, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 403 EP 408 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700046 ER PT S AU Owens, JM Johnson, MB AF Owens, JM Johnson, MB GP IEEE IEEE TI Interplanetary small mission studies SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Small missions can play a large role in future robotic space exploration. While these missions cannot accomplish the vast scope of science objectives achieved by large missions such as Mars Sample Return or Cassini, they offer opportunities to explore smaller., but pertinent, science goals for significantly reduced total mission cost. The Jet Propulsion Laboratory's Advanced Projects Design Team (Team X) has conducted several mission studies to explore the feasibility of scientifically significant small interplanetary missions. These mission studies encompassed various targets (Mars, Earth's Moon, Venus, the Sun) using several scientific payloads (radar, imagers, radiometers). These missions can also perform other functions such as probe/balloon delivery or communications; relay for landed missions. The studies considered a range of secondary payload launch vehicle options. This paper will highlight the results from these studies and discuss how the concurrent engineering environment of Team X lends itself to pre-phase A concept investigations. C1 CALTECH, Jet Prop Lab, Adv Projects Design Team Team X, Pasadena, CA 91109 USA. RP Owens, JM (reprint author), CALTECH, Jet Prop Lab, Adv Projects Design Team Team X, M-S 301-485,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 409 EP 423 PG 15 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700047 ER PT S AU Williams, TD Owens, JM Easter, RW Mireles, OR Ramsey, SA Palko, CW AF Williams, TD Owens, JM Easter, RW Mireles, OR Ramsey, SA Palko, CW GP IEEE IEEE TI Future Mars Outpost architecture SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB NASA's Mars Exploration Program includes science goals related to life, climate, geology, and preparation for human exploration. Many of the investigations needed to reach these goals are enabled by long-term, continuous surface presence with logistical support. These capabilities can be provided by a progressive series of missions that establish and maintain a long-lived robotic presence, i.e. a Mars Outpost. To investigate the issues associated with robotic outpost design, the JPL Mars Long Range Planning Team developed and studied a heuristic outpost scenario. Major goals of the study included identifying: (1) which science objectives benefit from an outpost setting, (2) technology needs to fulfill mission requirements, and (3) operational/logistical challenges associated with multimission planning. This paper describes an outpost designed with the aforementioned goals in mind. The design focuses on subsurface mapping and characterization, accomplished through seismic mapping and deep drilling. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Williams, TD (reprint author), CALTECH, Jet Prop Lab, JPL M-S 301-490,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 425 EP 440 PG 16 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700048 ER PT S AU Cornford, SL Feather, MS Hicks, KA AF Cornford, SL Feather, MS Hicks, KA GP IEEE IEEE TI DDP - A tool for life-cycle risk management SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB At JPL we have developed, and implemented, a process for achieving life-cycle risk management(*). This process has been embodied in a software tool and is called Defect Detection and Prevention (DDP). The DDP process can be succinctly stated as: determine where we want to be, what could get in the way and how we will get there. The 'determine where we want to be' is captured as trees of requirements and the 'what could get in the way' is captured as trees of potential failure modest. Scoring the impacts of these failure modes on the requirements results in a prioritized set of failure modes. The user then selects from a set of PACTs (Preventative measures, Analyses, process Controls and Tests) each of which has an effectiveness versus the various failure modes. It is the goal of the DDP process to optimally select the subset of the PACTs(double dagger) which minimizes the residual risk subject to the project resource constraints. The DDP process is intended to facilitate risk management over the entire project life cycle beginning with architectural and advanced technology decisions all the way through operation. As the project design, technology content and implementation approach matures, the requirements and failure mode trees are elaborated upon to accommodate the additional information. Thus, the DDP process is a systematic, continuous, top-down approach to managing risk. Implementation of the DDP process requires a critical mass of expertise (usually the project team and a few specialists) and captures both their engineering judgement as well as available quantitative data. This additional data may result from models, layouts, prototype testing, other focused risk evaluations and institutional experiences. The DDP process also identifies areas where additional information would be advantageous, thus allowing a project to target critical areas of risk or risk uncertainty. This also allows the project to identify those areas which would benefit the most from application of other quantitative tools and methods (e.g. Monte Carlo simulations, FMECAs, fault trees). The software tool supports the DDP process by providing guidance for implementing the process steps, graphical visualizations of the various trees, their interrelationships and the current risk landscape. The tool is capable of supporting on-the-fly knowledge elicitation as well as integrating-off-line deliberations. There are a variety of available outputs including graphs, trees and reports as well as clear identification of the driving requirements. 'tall-pole' residual risks and the PACTs which have been selected and agreed upon. The DDP process has been applied at various levels of assembly including the system and subsystem levels, as well as down to the component level. Recently significant benefits have been realized from application to advanced technologies, where the focus has been on increasing the infusion rates of these technologies by identification and mitigation of risks prior to delivery to a project. C1 CALTECH, Jet Prop Lab, Strateg Syst Technol Program Off, Pasadena, CA 91109 USA. RP Cornford, SL (reprint author), CALTECH, Jet Prop Lab, Strateg Syst Technol Program Off, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 3 Z9 3 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 441 EP 451 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700049 ER PT S AU Basilio, RR Plourde, KS Lam, T AF Basilio, RR Plourde, KS Lam, T GP IEEE IEEE TI A systematic risk management approach employed on the CloudSat project SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The CloudSat Project has developed a simplified approach for fault tree analysis and probabilistic risk assessment. A system-level fault tree has been constructed to identify credible fault scenarios and failure modes leading up to a potential failure to meet the nominal mission success criteria. Risk ratings and fault categories have been defined for each low-level event (failure mode) and a streamlined probabilistic risk assessment has been completed. Although this technique or process will mature and evolve on a schedule that emphasizes added value throughout the development life cycle, it has already served to confirm that project personnel are concentrating risk reduction or elimination/retirement measures in the appropriate areas. A cursory evaluation with an existing fault tree analysis and probabilistic risk assessment software application has helped to validate this simplified approach. It is hoped that this will serve as a model for other NASA flight projects. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Basilio, RR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 469 EP 479 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700051 ER PT S AU Hoffman, T Guiar, C AF Hoffman, T Guiar, C GP IEEE IEEE TI X2000/IFDP system engineering process for risk management SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB This paper describes some of the processes employed by the X2000/IFDP system engineering team to manage risk. This paper will describe the difficult system engineering task undertaken by the X2000/IFDP team of trying to develop a technology rich avionics system for a divergent interplanetary mission set. The ability to balance the risks inherent in technology development against the tight requirements of interplanetary missions was the job of the system engineering team. This job posed a unique set of challenges for the team requiring that new processes be developed. Many of the successful processes employed by the X2000/IFDP System Engineering team will be discussed in detail. The bottom line of each of the processes involved early and deep involvement by each of the affected subsystems. This allowed the system design issues to be worked in sufficient detail that the requirements and associated risks could be clearly identified. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hoffman, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 481 EP 493 PG 13 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700052 ER PT S AU Mandl, D Howard, J AF Mandl, D Howard, J GP IEEE IEEE TI How EO-1 used operations to cost-effectively mitigate risk SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB In recent years, NASA has been using the "Better, Faster, Cheaper" paradigm to create its missions. However, missions continue to get more complex despite being budget constrained. The first area to suffer in this situation is frequently the risk mitigation effort. Recent mission failures at NASA have caused the risk tolerance pendulum to swing back towards increased aversion to risk and thereby requiring more risk management in the development of missions and their corresponding spacecrafts. The need at this time is to find ways to manage risk in a cost-effective manner. This paper is about the steps that Earth-observing 1(EO-1), a Technology Validation mission, took to make risk-management more cost-effective. This was accomplished by first creating categories of success criteria. Operational staff was then applied against one or more categories of success criteria. The categories for success were minimally successful, successful and completely successful. In this way, operational staff could be planned and replanned using risk as a metric. This approach to risk mitigation was an order of magnitude less costly then taking a spacecraft architecture augmentation approach. The interesting thing about this mission is that during the development cycle, the required level of risk mitigation changed since NASA policy changed due to the recent mission failures. This new approach to risk management allowed more rapid adaptation to unforeseen changes in requirements since it was easier to identify risk impacts and resultant operations changes needed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mandl, D (reprint author), NASA, Goddard Space Flight Ctr, Code 584, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 495 EP 503 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700053 ER PT S AU Boyd, RW AF Boyd, RW GP IEEE IEEE TI Managing schedule and financial risk: Lessons learned on X2000 SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The X2000 Program is a technology development program that will provide next generation Avionics for missions to deep space. The goal of the X2000 Program is to develop revolutionary flight and ground systems which can be replicated by missions at a low cost, affording timely new science and mission opportunities to investigators and institutions. With the implementation of shorter development phases for projects, the need for better metrics to track a project's status became necessary. This paper will describe different methods for tracking such performance. Schedule performance will be discussed using Event-Driven Performance Assessment Metrics. Receivables/Deliverables, Slack tables, etc. Financial performance will be addressed by discussion of Earned Value (cost variance/schedule variance), cash flow. reserves management, risk reduction funds, etc. Although X2000 IFDP is not a flight project, it is delivering hardware to other projects and is being managed as if it were a flight project. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Boyd, RW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 505 EP 512 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700054 ER PT S AU Catena, J Casasanta, R Saylor, R Weikel, C AF Catena, J Casasanta, R Saylor, R Weikel, C GP IEEE IEEE TI Ground data system risk mitigation techniques for faster, better, cheaper missions SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB With the advent of faster, better and cheaper missions, NASA Projects acknowledged that a higher level of risk was inherent and acceptable with this approach. It was incumbent however upon each component of the Project, whether spacecraft, payload, launch vehicle or ground data system, to ensure that the mission would nevertheless be an unqualified success. The Small Explorer (SMEX) program's ground data system (GDS) team developed risk mitigation techniques to achieve these goals starting in 1989. These approaches have developed through the SMEX series of missions and are practiced today under the Triana program. These techniques are: 1. Mission Team Organization - empowerment of a close-knit ground data system team comprising system engineering, software engineering, testing, and flight operations personnel, 2. Common Spacecraft Test & Operational Control System - utilization of the pre-launch spacecraft integration system as the post-launch ground data system on-orbit command and control system, 3. Utilization of operations personnel in pre-launch testing - making the flight operations team an integrated member of the spacecraft testing activities at the beginning of the spacecraft fabrication phase, 4 Consolidated Test Team - combining system, mission readiness and operations testing to optimize test opportunities with the ground system and spacecraft, and 5. Reuse of Spacecraft, Systems, Standards, and People obtaining greater efficiencies through reuse of common spacecraft components, flight and ground-based subsystems, standardized interfaces, and project team personnel. The SMEX ground system development approach for faster, better, cheaper missions has been very successful. This paper will discuss these risk management techniques in the areas of ground data system design, implementation, test and operational readiness. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Catena, J (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 513 EP 521 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700055 ER PT S AU Hughes, SP Mailhe, LM AF Hughes, SP Mailhe, LM GP IEEE IEEE TI A preliminary formation flying orbit dynamics analysis for Leonardo-BRDF SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Leonardo-BRDF is a new NASA mission concept proposed to allow the investigation of radiative transfer and its effect on the Earth's climate and atmospheric phenomenon. Enabled by the recent developments in small-satellite and formation flying technology, the mission is envisioned to be composed of an array of spacecraft in carefully designed orbits. The different perspectives provided by a distributed array of spacecraft offer a unique advantage to study the Earth's albedo. This paper presents the flight dynamics analysis performed in the context of the Leonardo-BRDF science requirements. First, the albedo integral is investigated and the effect of viewing geometry on science return is studied. The method used in this paper, based on Gauss quadrature, provides the optimal formation geometry to ensure that the value of the integral is accurately approximated. An orbit design approach is presented to achieve specific relative orbit geometries while simultaneously satisfying orbit dynamics constraints to reduce formation-keeping fuel expenditure. The relative geometry afforded by the design is discussed in terms of mission requirements. An optimal Lambert initialization scheme is presented with the required DeltaV to distribute all spacecraft from a common parking orbit into their appropriate orbits in the formation. Finally, formation-keeping strategies are developed and the associated DeltaV's are calculated to maintain the formation in the presence of perturbations. C1 NASA, Goddard Space Flight Ctr, Flight Dynam Anal Branch, Greenbelt, MD 20771 USA. RP Hughes, SP (reprint author), NASA, Goddard Space Flight Ctr, Flight Dynam Anal Branch, Code 572, Greenbelt, MD 20771 USA. NR 13 TC 2 Z9 2 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 579 EP 596 PG 18 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700060 ER PT S AU Leitner, J AF Leitner, J GP IEEE IEEE TI A hardware-in-the-loop testbed for spacecraft formation flying applications SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Formation Flying Test Bed (FFTB) at NASA Goddard Space Flight Center (GSFC) is being developed as a modular, hybrid dynamic simulation facility employed for end-to-end guidance, navigation, and control (GN&C) analysis and design for formation flying clusters and constellations of satellites. The FFTB will support critical hardware and software technology development to enable current and future missions for NASA, other government agencies, and external customers for a wide range of missions, particularly those involving distributed spacecraft operations. The initial capabilities of the FFTB are based upon an integration of high fidelity hardware and software simulation, emulation, and test platforms developed at GSFC in recent years; including a high-fidelity GPS simulator which has been a fundamental component of the Guidance, Navigation, and Control Center's GPS Test Facility. The FFTB will be continuously evolving over the next several years from a tool with initial capabilities in GPS navigation hardware/software-in-the-loop analysis and closed loop GPS-based orbit control algorithm assessment to one with cross-link communications and relative navigation analysis and simulation capability. Eventually the FFTB will provide full capability to support all aspects of multi-sensor, absolute and relative position determination and control, in all (attitude and orbit) degrees of freedom, as well as information management for satellite clusters and constellations. In this paper we focus on the architecture for the FFTB as a general GN&C analysis environment for the spacecraft formation flying community inside and outside of NASA GSFC and we briefly reference some current and future activities which will drive the requirements and development. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leitner, J (reprint author), NASA, Goddard Space Flight Ctr, Code 571, Greenbelt, MD 20771 USA. NR 4 TC 6 Z9 6 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 615 EP 620 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700063 ER PT S AU Rabideau, G Reder, L Chien, S Booth, A AF Rabideau, G Reder, L Chien, S Booth, A GP IEEE IEEE TI Automated planning for interferometer configuration and control SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB In this paper, we discuss Artificial Intelligence (AI) planning and scheduling technology and its application to interferometer configuration and control. Scientific demand and technical requirements necessitate streamlining and optimizing the operation of these instruments. However, it is difficult, often impossible, to achieve this streamlining manually. Moreover, harsh operating environments make manual operation impractical, further motivating the use of automation. We describe the use of the ASPEN automated planning system developed at JPL to demonstrate how planning can be used to perform many operations tasks with many benefits over manual operations. Automated planners can rapidly produce large command sequences. In addition, repairing altered plans is very fast and can be used to respond to unforeseen events. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rabideau, G (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 629 EP 638 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700065 ER PT S AU Mackey, R AF Mackey, R GP IEEE IEEE TI Generalized cross-signal anomaly detection on aircraft hydraulic system SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB This paper outlines the mathematical foundation for a general method of anomaly detection from time-correlated sensor data. This method is a component of BEAM [1], described elsewhere, but as an individual algorithm is capable of fault detection and partial classification. The method is applicable to a broad class of problems and is designed to respond to any departure from normal operation, including faults or events that lie outside the training envelope. We will also consider training of the detector and interface to a larger diagnostic system. Lastly we will examine a brief illustration taken from aircraft testing that demonstrates the power and versatility of this method. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mackey, R (reprint author), CALTECH, Jet Prop Lab, Mail Stop 126-147,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 657 EP 667 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700068 ER PT S AU Zak, M Park, H AF Zak, M Park, H GP IEEE IEEE TI Gray-box approach to fault diagnosis of dynamical systems SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Model-based fault diagnosis has become an important approach for diagnosis of dynamical systems. By comparing the observed sensor values with those of the predicted values by the model, e.g., the residual, the health of the system can be assessed. However, because of modeling errors, sensor noise, disturbances, etc., direct comparison between observed and predicted values can be difficult. In effort to address this problem. we present a new method called the gray-box method. It is called a "gray-box" because a deterministic model of system, i.e., "white box," is used to filter the data and generate a residual, while a stochastic model, i.e., "black-box" is used to describe the residual. Instead of setting a threshold on the residual, the residual is modeled by a three-tier stochastic model. The linear and non-linear components of the residual are described by an auto-regressive process, and a time-delay feed-forward neural network, respectively. The last component, the noise, is characterized by its moments. The stochastic model provides a complete description of the residual, and the faults can be detected by monitoring the parameters of the auto-regressive model, the weights of the neural network, and the moments of noise. The method is robust to system modeling errors and is applicable to both linear and non-linear systems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zak, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 669 EP 675 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700069 ER PT S AU Spitz, S Prata, A Harrell, J Perez, R Veruttipong, W AF Spitz, S Prata, A Harrell, J Perez, R Veruttipong, W GP IEEE IEEE TI A 94 GHz spaceborne cloud profiling radar antenna system SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The CloudSat spacecraft, scheduled to launch in 2003, will carry a 94 GHz cloud profiling radar. The electrical design of its antenna system has been completed and is presented here. It consists of a quasi-optical transmission line that performs signal relaying and duplexing (using a Faraday rotator), and a collimating antenna that provides the required gain and spatial resolution. A shaped open Cassegrain collimating antenna is used because of its clear aperture, which allows for accurate electrical modeling, good performance, and significant reduction in implementation time and cost. The complete antenna system (horns to free space) has a worst case predicted gain of 63.1 dBi (59% efficiency) and exceeds the sidelobe envelope requirement of 50 dB below the peak gain at angles from boresight greater than 7 degrees. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Spitz, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 685 EP 692 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700071 ER PT S AU Hilland, J Bard, S Key, R Kim, Y Vaze, P Huneycutt, B AF Hilland, J Bard, S Key, R Kim, Y Vaze, P Huneycutt, B GP IEEE IEEE TI Dual frequency Synthetic Aperture Radar (SAR) mission for monitoring earth SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Advances in spaceborne Synthetic Aperture Radar (SAR) remote sensing technology make it possible to acquire global-scale data sets that provide unique information about the Earth's continually changing surface characteristics. Short duration missions such as the Spaceborne Imaging Radar-C (SIR-C) and the Shuttle Radar Topography Mission (SRTM) have established the vast potential of SAR for expanding our knowledge of Earth [1-3]. A long-duration (greater than or equal to 5 year) free-flying SAR mission is essential to routinely provide valuable information about the dynamic characteristics of our planet. The SAR mission concept, consists of a dual frequency, polarimetric, interferometric system that has broad scientific, environmental preservation, operational, and commercial utility. A feature that greatly reduces the potential for tasking conflicts is the instrument's ability to operate both frequencies independently and simultaneously. The implementation approach includes an innovative government-industry collaboration that has the potential to lead to the creation of new information industries, in a manner similar to the Internet, Global Positioning Satellite (GPS) and commercial space telecommunications. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Hilland, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 719 EP 724 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700074 ER PT S AU Stosic, DK Hatch, WA Lux, JP McMaster, RL AF Stosic, DK Hatch, WA Lux, JP McMaster, RL GP IEEE IEEE TI Utilizing off-the-shelf parts for the next generation of space exploration SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Common components were evaluated for use in an orbiting Ku-band polarimetric scatterometer that will enable measurements of near-surface wind speeds for over 90% of the ice-free oceans. Designed as a successor to Seawinds, the new design may require two matched RF chains to attain adequate performance. Off-the-shelf DBS (Direct Broadcast System) and telecom components have significant potential to reduce development and equipment costs. However, space flight systems have requirements that are qualitatively different from the commercial or consumer applications for which the majority of new RF products are developed. Furthermore, the 13.402GHz center frequency for scatterometers is somewhat higher than the commercial 12GHz; DBS band. Consequently, Jet Propulsion Laboratory (JPL) tested and evaluated these parts, and at present, work reports on RF performance measurements of selected commercial Monolithic Microwave Integrated Circuit (MMIC) components are encouraging and appear suitable for space applications. For evaluation, two MMIC Low Noise Amplifiers (LNA) (Filtronic, LMA246 and TriQuint (R), TGA8399B) and one mixer (Remec, part #MM84MS-14) were selected. Test fixtures were constructed for the MMIC parts, which were then carefully examined in several test setups. Both dual and single chain configurations were necessary to completely define each component, where noise figure and gain tests of the Ku-band amplifiers were completed. Of more importance to the polarimetric application, the stability of relative phase and gain tracking with respect to temperature was extensively characterized in a variety of candidate LNA/mixer configurations. While the initial RF evaluation looks promising, further evaluation of these parts (radiation tolerance, reliability, etc.) will be required for flight qualification. "Upscreened" Commercial, off-the-shelf (COTS) parts, in space applications are especially encouraging when the possibility of capitalizing on their extensive development for high-volume consumer applications is considered. Other applications for MMIC parts in space could possibly open new doors in the future. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Stosic, DK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 733 EP 739 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700076 ER PT S AU Imbriale, WA AF Imbriale, WA GP IEEE IEEE TI Distortion compensation techniques for large reflector antennas SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The high-frequency limit of reflector antennas is usually governed by the magnitude of the surface error. Whereas little can be done for the high-spatial frequency portion of this error, there are various techniques that can be employed to compensate for large-scale surface errors due to gravity induced distortions for ground antennas or thermally induced distortions for spacecraft antennas. This somewhat tutorial paper describes various techniques that can be utilized to compensate for the gain-loss due to these distortions. The techniques described are 1) Main reflector compensation, 2) Subreflector compensation, 3) Use of a deformable flat plate in the optics path and 4) an Array feed compensation system. Examples are give for the use of each technique along with an estimate of the expected performance improvement. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Imbriale, WA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 799 EP 805 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700084 ER PT S AU Losh, D Vodonos, Y Conroy, B Silva, A McDowall, G Ocampo, J AF Losh, D Vodonos, Y Conroy, B Silva, A McDowall, G Ocampo, J GP IEEE IEEE TI New 20-kW CW transmitter for NASA's Deep Space Network SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB A 20-kW S- and X-Band transmitter was developed for NASA's Deep Space Network (DSN) 70-m antennas. The transmitter consists of two separate high-power amplifiers and common supporting assemblies. The new design includes innovations in control and monitoring that simplify the overall transmitter implementation and substantially improve its maintainability. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Losh, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 819 EP 828 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700086 ER PT S AU Bautista, JJ Bowen, JG Fernandez, JE Fujiwara, B Loreman, J Petty, S Prater, JL Murti, MR AF Bautista, JJ Bowen, JG Fernandez, JE Fujiwara, B Loreman, J Petty, S Prater, JL Murti, MR GP IEEE IEEE TI Cryogenic, X-band and Ka-band InPHEMT based LNAs for the Deep Space Network SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID NOISE PARAMETERS; TRANSISTORS; TEMPERATURE AB Exploration of the Solar System with automated spacecraft that are more than ten astronomical units from earth requires very large antennae employing extremely sensitive receivers. A key figure of merit in the specification of the spacecraft-to-earth telecommunications link is the ratio of the antenna gain to operational noise temperature (G/Top) of the system. The Deep Space Network (DSN) receivers are cryogenic, low-noise amplifiers (LNAs) which address the need to maintain Top as low as technology permits. Historically, the extra-ordinarily sensitive receive systems operated by the DSN have employed cryogenically cooled, ruby masers as the INA. Recent advances in the development of indium phosphide (InP) based high electron mobility transistors (HEMTs) combined with cryogenic cooling have made this technology competitive with standard DSN maser technology. InP HEMT LNA modules are demonstrating noise temperatures less than ten times the quantum noise limit (10hf/k) from 1 to 100 GHz. To date, the lowest noise LNA modules developed for the DSN have demonstrated noise temperatures of under 4 K at 8.4 GHz and 11 K at 32 GHz. Front-end receiver packages employing these modules demonstrated operating system noise temperatures of 17 K at 8.4 GHz (on a 70m antenna at zenith) and 39.4 K at 32 GHz (on a 34m antenna at zenith). The development and demonstration of cryogenic, InP HEMT based front-end amplifiers for the DSN requires accurate component and module characterization, and modeling from 1 to 100 GHz at physical temperatures down to and below 12 K, because of the broad band frequency response of InP HEMTs. The characterization and modeling begins with the HEMT chip, proceeds to the multi-stage HEMT LNA module, and culminates with the complete front-end cryogenic receiver package for the antenna. This paper presents an overview of this development process with emphasis on comparison between modeled and measured results at 8.4 GHz. Results will be shown for devices, LNA modules, front-end receiver packages employing these modules, and antennae employing these packages. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bautista, JJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 0 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 829 EP 842 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700087 ER PT S AU Jamnejad, V Huang, J Endler, H Manshadi, F AF Jamnejad, V Huang, J Endler, H Manshadi, F GP IEEE IEEE TI Small Omni-directional antenna development for Mars Sample Return mission SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB This work addresses the design, analysis and test of omni-directional antennas at 401.5 MHz and 437.1 MHz frequencies, on Mars Orbital Sample (OS) return canisters, which are part of a Mars Sample Return (MSR) mission. The OS in Mars orbit will have a tumbling random orientation. The OS antennas are electrically small (on the order of 0.2 wavelength or less) and linearly polarized. Either a single antenna with two resonant frequencies and a diplexer to provide isolation, or a two-antenna system with a natural isolation of at least 10 dB between the antenna input ports are needed. In this paper results of theoretical and experimental studies on several different types of antennas appropriate to this application are presented. Many of these antennas are designed, fabricated, and tested, and their critical parameters are addressed and investigated. Acceptable near omnidirectional pattern coverage and minimum gain levels of better than -2 dB are obtained. These antennas include dual circular patch antennas with slots used to shorten the dimensions, very small square patch antennas with ultra high dielectric ceramic substrates, narrow width patch (ribbon) antennas wrapped around the spherical shell, top-loaded monopoles with different load configurations, and variant PIFA type antennas similar to those used in wireless systems. Many numerical and experimental results are presented and future efforts to further improve the performance are outlined. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jamnejad, V (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 843 EP 851 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700088 ER PT S AU Cwik, T Katz, DS Villegas, F AF Cwik, T Katz, DS Villegas, F GP IEEE IEEE TI Integrated design and simulation for millimeter-wave antenna systems SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Several instruments operating in the microwave and millimeter-wave bands are to be developed over the next several years at JPL or in conjunction with various other companies and laboratories. The design and development of these instruments requires an environment that can produce a microwave or millimeter-wave optics design, and can assess sensitivity of key design criteria (beamwidth, gain, sidelobe levels, etc.) to thermal and mechanical operating environments. An integrated design tool has been developed to carry out the design and analysis using software building blocks from the computer-aided design, thermal, structural and electromagnetic analysis fields. The capability to simultaneously assess the effects of design parameter variation resulting from thermal and structural loads can reduce design and validation cost and generally lead to more optimal designs, hence higher performing instruments. In this paper the development and application of MODTool (Millimeter-wave Optics Design), a design tool that efficiently integrates existing millimeter-wave optics design software with a solid body modeler and with thermal and structural analysis packages will be discussed. The design tool is also directly useful over other portions of the spectrum, though thermal or dynamic loads may have less influence on antenna patterns at the longer wavelengths. Under a common interface, interactions between the various components of a design can be efficiently evaluated and optimized. One key component is the use of physical optics analysis software for antenna pattern analysis. This software has been ported to various platforms including distributed memory parallel supercomputers to allow rapid turn-around for electrically large designs. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cwik, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 899 EP 907 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700094 ER PT S AU Bhasin, K Hayden, JL AF Bhasin, K Hayden, JL GP IEEE IEEE TI Space Internet architectures and technologies for NASA enterprises SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB NASA's future communications services will be supplied through a space communications network that mirrors the terrestrial Internet in its capabilities and flexibility. The notional requirements for future data gathering and distribution by this Space Internet have been gathered from NASA's Earth Science Enterprise (ESE), the Human Exploration and Development in Space (HEDS), and the Space Science Enterprise (SSE). This paper describes a communications infrastructure for the Space Internet, the architectures within the infrastructure, and the elements that make up the architectures. The architectures meet the requirements of the enterprises beyond 2010 with Internet compatible technologies and functionality, The elements of an architecture include the backbone, access, inter-spacecraft, and proximity communication parts. From the architectures, technologies have been identified which have the most impact and are critical for the implementation of the architectures. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Bhasin, K (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd,MS 54-2, Cleveland, OH 44135 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 931 EP 941 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700098 ER PT S AU Clare, LP Agre, JR Yan, TY AF Clare, LP Agre, JR Yan, TY GP IEEE IEEE TI Considerations on communications network protocols in deep space SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Deep space missions impose numerous unique constraints that impact the communications architectural choices. We are entering the era where networks that exist in deep space are needed to support planetary exploration. Identification is made of the various distinctive elements that drive the selection of the communications protocol suite. Cost-effective performance will require a balanced integration of applicable widely used standard protocols with new and innovative designs. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Clare, LP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 18 TC 3 Z9 4 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 943 EP 950 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700099 ER PT S AU Spinolo, MC AF Spinolo, MC GP IEEE IEEE TI Commercial and Internet trends and the NASA spaceflight ground network SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB (1)NASA is a critical information source in this Age of Information. With the advent and maturity of the Internet, the demand for NASA information has grown beyond science data archives to near real time and even real time data, particularly on the Earth and near Earth ecosystems. NASA also has prospered a policy of sharing mission responsibility with non-NASA entities, which still require tracking support from the NASA network. This paper discusses the issues in conflict when trying to solve the paradox of securing a critical national resource and participating as a good citizen of the Information Age. By illustrating several ground network architecture examples, these issues are highlighted. Recommendations for using the NASA tracking networks are given. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Spinolo, MC (reprint author), NASA, Goddard Space Flight Ctr, Code 291, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1021 EP 1026 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700105 ER PT S AU Alena, R Gilbaugh, B Glass, B Braham, SP AF Alena, R Gilbaugh, B Glass, B Braham, SP GP IEEE IEEE TI Communication system architecture for planetary exploration SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Future human missions to Mars will require effective communications supporting exploration activities and scientific field data collection. Constraints on cost, size, weight and power consumption for all communications equipment make optimization of these systems very important. These information and communication systems connect people and systems together into coherent teams performing the difficult and hazardous tasks inherent in planetary exploration. The communication network supporting vehicle telemetry data, mission operations, and scientific collaboration must have excellent reliability and flexibility. We propose hybrid communication architectures consisting of space-based links, a surface-based deployable mid-range communications network and a cluster of short-range links to solve the problems of connectivity and bandwidth, while meeting the other constraints of weight and power. A network of orbiting satellites could cover much of the planet surface, but this space-based capability may not be optimal for cost or performance. Specifically, a minimal space-based capability can be augmented using mobile cellular repeaters deployable by robots and human EVA. This method results in an increase in the number of radio nodes, but the distances separating them is decreased. This results in a significant increase in bandwidth and decrease in radio power and therefore node size, complexity and power consumption. The paper will discuss the results of field-testing such hybrid radio systems for the support of scientific surveys. System analysis of design tradeoffs will yield insight into optimal solutions that will be compared to other approaches providing a method of effectively evaluating new candidate architectures. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Alena, R (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1075 EP 1084 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700111 ER PT S AU Gilbaugh, BL Glass, B Alena, R AF Gilbaugh, BL Glass, B Alena, R GP IEEE IEEE TI Mobile network field testing at HMP-2000 SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Future human planetary exploration field teams will need daily communications with their base and with mission control. A remote field wireless digital network will be a requirement for safe and productive human exploration. Proper selection of radio-frequency hardware and antennas will be vital to its success in remote, hostile environments. This paper reviews the communications techniques explored in the Mobile Exploration 2000 field season at the Haughton-Mars Project, which was located at a remote impact crater field science site in the Canadian Arctic. Results from 2.4GHz spread-spectrum signal-strength and data throughput tests, conducted during remote field deployments, show a marked variability with given hardware and antenna choices, with directional antenna performance less than expected from theory. Changing the antenna schemes for repeater-to-base and repeater-to-rover increased the rover's effective communication range to base camp to over 3km. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Gilbaugh, BL (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1085 EP 1092 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700112 ER PT S AU Berner, JB Kinman, PW Sue, MK AF Berner, JB Kinman, PW Sue, MK GP IEEE IEEE TI Dynamic telemetry bit rates for deep space communications SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB A new telemetry playback scheme promises to maximize telemetry return for deep space missions. For a given effective isotropic radiated power from the spacecraft, the received signal-to-noise spectral density ratio and hence the supportable bit rate vary during a tracking pass as the elevation angle changes. In the past, spacecraft would use just one bit rate or perhaps a few different bit rates during a pass. However, large bit rate changes sometimes cause the ground receiver to go out of lock. The new scheme, which is examined here, allows the spacecraft to change its bit rate in frequent, small steps to match the signal-to-noise spectral density ratio profile. Because the rate changes are small, the ground receiver will be able to remain in lock. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Berner, JB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 238-737, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1143 EP 1148 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700119 ER PT S AU Berner, JB Andrews, KS AF Berner, JB Andrews, KS GP IEEE IEEE TI Deep space network turbo decoder implementation SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB A new decoder is being developed by the Jet Propulsion Laboratory for NASA's Deep Space Network. This unit will decode the new turbo codes, which have recently been approved by the Consultative Committee for Space Data Systems (CCSDS). Turbo codes provide up to 0.8 dB improvement in E-b/N-0 over the current best codes used by deep space missions. The new decoder is being implemented in software running on commercial Digital Signal Processor (DSP) chips, removing the need to design complicated and expensive hardware as was the case with the previous generation of codes. The decoder will time-tag the data frames, perform frame synchronization in the symbol domain (as opposed to the current bit domain synchronization), decode the turbo coded frames, and output the decoded bits in the CCSDS Standard Formatted Data Units format. The decoder is initially designed to operate up to 365 kbps, but will increase in rate as DSP clock rates increase. The implementation,will go operational in October, 2003. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Berner, JB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1149 EP 1157 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700120 ER PT S AU Hurd, WJ Mileant, A AF Hurd, WJ Mileant, A GP IEEE IEEE TI Improved carrier tracking for low-threshold telemetry using a smoother SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB This work establishes the threshold performance of noncausal smoothing filters used for tracking residual carrier signals when performance is limited by both phase process noise and additive receiver noise. Previous work [1] based entirely on linear theory predicts significant improvements in phase estimation by using smoothing filters as compared with using causal phase-locked loops (PLLs). For phase process noise having a 1/f(3) spectral density, which is typical of many oscillators, linear theory predicts a reduction in phase estimation error of 5 dB for the same phase-noise and receiver-noise magnitudes. Alternatively, linear theory predicts the ability of a smoother to track a 7.5-dB weaker signal with the same mean-square phase error, under the same conditions of phase process noise. Simulations show that the smoothers achieve an effective loop signal-to-noise ratio (SNR) within 0.5 dB of linear theory when the linear theory predicts an effective loop SNR as low as 11.4 dB. Under the same conditions, an optimum PLL would have a linear-model effective loop SNR of only 6.4 dB and would perform more than 1-dB worse that this, with many cycle slips. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hurd, WJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1167 EP 1178 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700122 ER PT S AU Fisher, F James, ML Paal, L Engelhardt, B AF Fisher, F James, ML Paal, L Engelhardt, B GP IEEE IEEE TI An architecture for an autonomous ground station controller SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Deep Space Station Controller (DSSC) is a state of the art ground station control architecture being developed at the Jet Propulsion Laboratory (JPL). The DSSC has been designed for robust closed loop control of ground communication stations utilized for communications with and commanding of NASA's deep space exploration missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fisher, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 126-347, Pasadena, CA 91109 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1179 EP 1187 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700123 ER PT S AU Mysoor, N Kayalar, S Andricos, C Walsh, GJ AF Mysoor, N Kayalar, S Andricos, C Walsh, GJ GP IEEE IEEE TI Performance of dielectric resonator oscillator for spacecraft transponding modem SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB A new Spacecraft Transponding Modem (STM) is being developed by the Jet Propulsion Laboratory for National Aeronautics and Space Administration (NASA) for deep space communication applications. The STM receives an X-band (7.17 GHz) uplink signal and generates an X-band (8.4GHz) and a Ka-band (32.0GHz) coherent or noncoherent downlink signals. The STM architecture incorporates three miniature dielectric-resonator-oscillators (DRO). These DROs are used in receiver and exciter frequency synthesis phase-locked loops (PLL) in the STM. The DROs are designed with custom developed monolithic microwave integrated circuit (MMIC) negative resistance oscillator chips. DROs are laid out on alumina substrates in RF cavity fixtures of 18mm, x 18mm x 8mm. The receiver and the exciter DRO designs meet the following requirements: frequency stability of +/- 2ppm/degreesC, the free running single-sideband phase noise of -50dBc at 1-kHz offset frequency, tuning linearity of +/- 10% over the +/-1.75-MHz locking range, and output power of + 10dBm +/- 1 dB over a design temperature range of -55 degreesC to +85 degreesC. The phase-locked loop DRO frequency synthesizers are designed using sampling downconverter and phase detector MMIC chips. These PLL frequency synthesizers meet the following requirements: pull-in range of +/-1.75MHz, loop noise bandwidth of 100kHz, and a single-sideband phase noise of -144dBc at 1-kHz offset frequency. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mysoor, N (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS-161-213, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1189 EP 1194 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700124 ER PT S AU Hansen, DM Sue, MK Ho, CM Connally, M Peng, TK Cesarone, RJ Horne, W AF Hansen, DM Sue, MK Ho, CM Connally, M Peng, TK Cesarone, RJ Horne, W GP IEEE IEEE TI Frequency bands for Mars in-situ communications SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The recent decision to send two rovers to Mars in 2003 has provided new direction for Mars exploration. To meet these future challenges, NASA's Jet Propulsion Laboratory (JPL) is preparing the Deep Space Network (DSN) and other communication systems to support the expected increase in Mars exploration activities. Toward this end, JPL is conducting studies to enhance communications and navigation capabilities on or around Mars for future Mars missions and is investing in hardware development for use by those missions. One such study is developing a multiple-access scheme and a frequency-utilization plan for in-situ communications and navigation. The results of this study will provide recommendations for developing communications hardware for future Mars missions, establishing interoperability processes and standards, ensuring access to the radio frequency spectrum for operations at Mars and fbr testing at Earth, and designing a communication and navigation infrastructure around Mars. This paper will focus on the selection of frequencies for local ("in situ") links at Mars. Various factors affecting the selection of frequencies, including link performance, propagation effects, and mission scenarios, will be discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hansen, DM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1195 EP 1208 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700125 ER PT S AU Kayalar, S Mysoor, N Andricos, C AF Kayalar, S Mysoor, N Andricos, C GP IEEE IEEE TI Development of linear phase modulator for Spacecraft Transponding Modem SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB A new Spacecraft Transponding Modem (STM) is being developed by the Jet Propulsion Laboratory for National Aeronautics and Space Administration (NASA) for deep space communication applications. The STM receives an X-band (7.17 GHz) uplink signal and generates an X-band (8.4 GHz) and a Ka-band (32.0 GHz) coherent or noncoherent downlink signals. The STM architecture incorporates two miniature linear phase modulators. These modulators are used to modulate the X-band and Ka-band downlink frequencies with the downlink telemetry, turnaround ranging, or regenerative PN-ranging signals. The linear phase modulators are designed with custom developed microwave monolithic integrated circuit (MMIC) chips. The phase modulator MMICs, the amplifiers, and driver circuits are laid out on drop-in alumina substrates. These modulator designs meet the following requirements: phase deviation range of +/- 140 degrees at X-band and Ka-band downlink carrier frequencies, phase linearity of less than 8%, phase modulation input bandwidth of greater than 100 MHz, and differential input with sinewave or squarewave modulating format. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kayalar, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS-161-213, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1233 EP 1241 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700128 ER PT S AU Bryant, S AF Bryant, S GP IEEE IEEE TI Using Digital Signal Processor technology to simplify deep space ranging SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Commercially available Digital Signal Processor (DSP) technology has enabled a modified design Deep Space Network (DSN) ranging system. The modified design eliminates custom correlator printed circuit boards in favor of Commercial Off The Shelf (COTS) DSPs. This reduces overall size, parts count, and complexity. Embedded DSP software will provide the flexibility to handle Pseudo-random Noise, sequential squarewave, or other periodic ranging tones. The design implementation will also meet the Jet Propulsion Laboratory (JPL) requirements for both near-Earth and deep space ranging. JPL's Network Simplification Project will consolidate the DSN ground system functions into less hardware and simplify network operations. This effort includes implementing the new spacecraft ranging design described here. This implementation will reduce the amount of ranging hardware (and thus maintenance) while increasing the operational flexibility. The new ranging implementation also provides a new DSN capability to support the new Spacecraft Transponding Modem [1] being developed at JPL. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bryant, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 238-737, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1277 EP 1282 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700132 ER PT S AU Robinson, DC AF Robinson, DC GP IEEE IEEE TI Air traffic control improvement using prioritized CSMA SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Version 7 simulations of the industry-standard network simulation software "OPNET" are presented of two applications of the Aeronautical Telecommunications Network (ATN), Controller Pilot Data Link Communications (CPDLC) and Automatic Dependent Surveillance-Broadcast mode (ADS-B), over VHF Data Link mode 2 (VDL-2). Communication is modeled for air traffic between just three cities. All aircraft are assumed to have the same equipage. The simulation involves Air Traffic Control (ATC) ground stations and 105 aircraft taking off, flying realistic free-flight trajectories, and landing in a 24-hr period. All communication is modeled as unreliable. Collision-less, prioritized carrier sense multiple access (CSMA) is successfully tested. The statistics presented include latency, queue length, and packet loss. This research may show that a communications system simpler than the currently accepted standard envisioned may not only suffice, but also surpass performance of the standard at a lower cost of deployment. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Robinson, DC (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1359 EP 1365 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700141 ER PT S AU Kerczewski, RJ Hoder, DJ Zakrajsek, RJ AF Kerczewski, RJ Hoder, DJ Zakrajsek, RJ GP IEEE IEEE TI Satellite communications for aeronautics applications - Technology development and demonstration SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The National Aeronautics and Space Administration (NASA) is performing research and development to improve the safety and increase the capacity of the National Airspace System (NAS). Improved communications, especially to and from the aircraft flight deck, has been identified as an essential enabling technology for future improvements to the air traffic management system and aviation safety. NASA's Glenn Research Center is engaged in research and development of satellite communications technologies for aeronautical applications. A mobile aero terminal has been developed for use with Ku Band commercial communications satellites. This experimental terminal will be used in mobile ground and air-based tests and demonstrations during 2000-2004. This paper will describe the basic operational parameters of the Ku Band aero terminal, the communications architecture it is intended to demonstrate, and the key technology issues being addressed in the tests and demonstrations. The design of the Ku Band aero terminal and associated ground testbed, planned tests and demonstrations, and results to date will be presented. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Kerczewski, RJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1367 EP 1373 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700142 ER PT S AU Zernic, MJ Freudinger, LC Morris, AT AF Zernic, MJ Freudinger, LC Morris, AT GP IEEE IEEE TI Aeronautical satellite assisted process for information exchange through network technology (Aero-SAPIENT) project: The initial trials SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The current National Air Space (NAS) infrastructure is becoming saturated with increased air travel and NASA is leading many technology activities that address aviation system capacity and safety concerns. The insertion of communication and networking technologies into the NAS promises greater connectivity, interactivity, and more effective decision making. The infrastructure will be enhanced to handle more traffic, provide safer operations, enable innovative flight operations services, and enable new cabin services. One such NASA activity is the Aeronautical Satellite Assisted Process for Information Exchange through Networking Technology (Acro-SAPIENT) project. This project includes the design of sub-system prototypes and the investigation of satellite-based data sharing, information integrity and security in a multi-protocol environment. This paper describes the technical objectives of the initial flight technology demonstration including the network and satellite communication technologies, as well as the utilization of various applications. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Zernic, MJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1375 EP 1384 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700143 ER PT S AU Zhang, XL AF Zhang, XL GP IEEE IEEE TI The wide-field imaging interferometry testbed SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB We are developing a Wide-Field Imaging Interferometry Testbed (WITT) in support of design studies for NASA's future space interferometry missions, in particular the SPIRIT and SPECS far-infrared/submillimeter interferometers. WHT operates at optical wavelengths and uses Michelson beam combination to achieve both wide-field imaging and high-resolution spectroscopy. It will be used chiefly to test the feasibility of using a large-format detector array at the image plane of the sky to obtain wide-field interferometry images through mosaicing techniques. In this setup each detector pixel records interferograms corresponding to averaging a particular pointing range on the sky as the optical path length is scanned and as the baseline separation and orientation is varied. The final image is constructed through spatial and spectral Fourier transforms of the recorded interferograms for each pixel, followed by a mosaic/joint-deconvolution procedure of all the pixels. In this manner the image within the pointing range of each detector pixel is further resolved to an angular resolution corresponding to the maximum baseline separation for fringe measurements. We present the motivation for building the testbed, show the optical, mechanical, control and data system design, and describe the image processing requirements and algorithms. WHT is presently under construction at NASA's Goddard Space Flight Center. C1 NASA, Goddard Space Flight Ctr, Raytheon ITSS, Greenbelt, MD 20771 USA. RP Zhang, XL (reprint author), NASA, Goddard Space Flight Ctr, Raytheon ITSS, Greenbelt, MD 20771 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1453 EP 1459 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700150 ER PT S AU Clouse, D Liebe, CC Padgett, C Bartman, R AF Clouse, D Liebe, CC Padgett, C Bartman, R GP IEEE IEEE TI Covering a sphere with retroreflectors SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB One of the future missions for Mars involves returning a soil sample from the Martian surface to Earth, The sample will be deposited in a spherical canister, shot into Mar's orbit and then subsequently captured by a spacecraft for the return journey. This paper discusses how retroreflectors can be placed on the orbiting sample canister with the objective of maximizing returned light from a scanning laser system. The retroreflectors are vital for acquisition of the sample canister during the terminal rendezvous phase (< 5 km) of the capture. The identification of a retroreflector configuration relies extensively on Monte Carlo simulations. Computer simulations show that a spherical t-design yields a strong return for a 50 retroreflectors constellation. The return is calculated utilizing formulas for Rayleigh-Sommerfeld diffraction, and integrating over the surfaces of the retroreflector apertures for the specific orientation of the spherical container. At a distance of 5 kin, in simulation the chosen configuration produces a return signal that is at least 5% of the return of a single retroreflector head-on approximately 99.99% of the time. On average, the return signal is 1.36 times the signal of a-single retroreflector head-on. The results of the model and empirical results collected at a shorter distance are consistent. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Clouse, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 1 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1495 EP 1506 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700155 ER PT S AU Monacos, SP Portillo, AA Liu, W Alexander, JW Ortiz, GG AF Monacos, SP Portillo, AA Liu, W Alexander, JW Ortiz, GG GP IEEE IEEE TI A high frame rate CCD camera with region-of-interest capability SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB This paper presents the design and preliminary results of a custom high-speed CCD camera utilizing a Texas Instruments TC237 CCD imager chip with sub-frame window read out. The camera interfaces to a C40 digital signal processor (DSP), which is used to issue commands and read images from the camera. The camera design consists of a two-card set including the CCD imager card and the focal plane array (FPA) interface card. The CCD imager card contains the level translator and buffer circuitry for the CCD strobe lines, the TC237 CCD imager chip and a pair of analog signal processor chips, each with a 10-bit analog-to-digital converter. The analog signal processor is a TLV987 with correlated double sampling (CDS) and serial programming capability to set amplifier gain, pixel bias level and background level illumination to name a few. The second card contains a pair of field programmable gate arrays (FPGA) used to interface the CCD imager card to the C40. The goal of this camera development is to provide a high-quality, high-speed camera as part of the tracking apparatus for a free-space optical communications terminal. Preliminary data suggests frame rates of 6KHz for 8x8 sub-windows in the current testbed with 7-bit pixel resolution. Refinements in camera and testbed operation target performance goals of 17KHz for 8x8 sub-windows with 10-bit pixel resolution. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Monacos, SP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 1 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1513 EP 1522 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700157 ER PT S AU Portillo, AA Ortiz, GG Racho, C AF Portillo, AA Ortiz, GG Racho, C GP IEEE IEEE TI Fine pointing control for optical communications SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc DE free-space optical communications; fine pointing control AB Free-Space Optical Communications requires precise, stable laser pointing to maintain optimal operating conditions. This paper describes the software and hardware implementation of the Fine Pointing Control based on the Optical Communications Demonstrator architecture. The implementation is designed to facilitate system identification of the Fast Steering Mirror mechanism. Models are derived from laboratory testing of two fine steering mirrors that are integrated into the fine tracking loop. Digital controllers are then designed to close the tracking loop using optical feedback. Results of the Fine Pointing Control performance show an improvement of 20% in the jitter rejection bandwidth over previous experiments. A discussion of the computer delay and limited processing bandwidth in this particular implementation are included. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Portillo, AA (reprint author), CALTECH, Jet Prop Lab, M-S 238-343,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 4 Z9 5 U1 2 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1541 EP 1550 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700160 ER PT S AU Lee, S Ortiz, GG Alexander, JW Portillo, A Jeppesen, C AF Lee, S Ortiz, GG Alexander, JW Portillo, A Jeppesen, C GP IEEE IEEE TI Accelerometer-assisted tracking and pointing for deep space optical communications SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB NASA/JPL has been developing acquisition, tracking and pointing (ATP) technologies for deep space tracking and pointing of an optical communication beam using linear accelerometers to enhance pointing. Linear accelerometers provide excellent accuracy in sensing the vehicle's acceleration with the advantage of small size, low power, low cost, and a broad range of well developed products. Accurate and stable pointing is the most critical function necessary to establish a successful free-space optical communication link. Generally known as the line of sight problem, it is also common to system requiring image stabilization, such as video cameras. The most dominant mis-pointing error source is spacecraft vibration that causes tine-of-sight jitter during beam pointing. Line of sight stabilization using the detection and measurement of spacecraft vibration has been previously pursued with gyros, angle sensors, and more recently, angular rate sensors. The goal of the ATP research is to achieve sub-microradian pointing for deep space optical communications. The most critical tracking parameter to achieve sub-microradian pointing under the spacecraft vibration is the tracking update rate. Since the degree of suppression of spacecraft vibration is proportional to the ability to measure it, faster measurements will improve the pointing. Current tracking systems rely on optical beacon sources such as ground based laser beacon, extended sources (such as Sun-illuminated Earth or Moon), and stars. However, for deep space ranges, the intensity of these beacon sources is not sufficient to support the required optical tracking rate that is often few kilohertz. However, the tracking rate can be increased by employing inertial sensors, which can propagate the line of sight between optical measurements, command the pointing mechanism compensating for the spacecraft vibrations, effectively increasing the tracking rate. In this paper, we will present the concept of accelerometer-assisted tracking, error analysis, and progresses made on its implementations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 1 Z9 3 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1559 EP 1564 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700162 ER PT S AU Liebe, CC Mobasser, S AF Liebe, CC Mobasser, S GP IEEE IEEE TI MEMS based sun sensor SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Sun sensors have been widely used as a part of spacecraft attitude determination subsystems to provide a measurement of the sun vector in spacecraft coordinates. An experimental Micro Electro Mechanical System (MEMS) based sun sensor is presented in this paper. This prototype sun sensor is comprised of a silicon wafer mask with several hundred small apertures placed on top of a Charge Coupled Device (CCD) focal plane array at a distance of 750 microns. An image of the apertures is formed on the focal plane when the sun illuminates this setup. Sun angles can be derived by analyzing the image. The experimental data presented indicates that this sun sensor can achieve accuracies on the order of a few arcminutes or better. It is projected that this type of sun sensor, utilizing an Active Pixel Sensor (APS) focal plane array, will be the size of three dimes stacked on top of each other. It will have a mass of less than 30g and consume less than 20 mW. This will make this type of sun sensor ideal for micro/nano spacecraft and small rovers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liebe, CC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 5 Z9 8 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1565 EP 1572 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700163 ER PT S AU Dorsky, LI AF Dorsky, LI GP IEEE IEEE TI Trends in instrument systems for deep space exploration SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Instrument systems for deep space exploration have undergone dramatic changes in the last few years. They are smaller, lighter and less power hungry. The line between science instruments and spacecraft sensors is blurring. New vehicles, missions, goals, environments and types of instruments are changing the design of instrument suites. Finally, integrated instrument suites are becoming more common. Using Cassini spacecraft instruments as a benchmark, instrument suites on the DS-I and DS-2 spacecraft are discussed along with designs for MECA, MER and the Subsurface Explorer, in the context of these trends. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dorsky, LI (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1573 EP 1582 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700164 ER PT S AU Larson, S Beer, R AF Larson, S Beer, R GP IEEE IEEE TI Overview of the Tropospheric Emission Spectrometer ground system SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Tropospheric Emission Spectrometer (TES) will provide the first three-dimensional (latitude/longitude and altitude) measurements of tropospheric ozone and related species. The scientific objectives of the TES project are discussed, and an overview of the experiment and mission plan are presented. An overview of the design of the ground system is provided as context to a description of how some of the unique challenges posed by the development of the TES ground system were addressed. The solutions described include: concurrent engineering of flight and ground systems, use of CASE tools in software development, use of work-stations clusters to meet computational requirements, and the development of a project-specific Framework. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Larson, S (reprint author), Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1601 EP 1610 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700167 ER PT S AU Tyler, SR Varanasi, P AF Tyler, SR Varanasi, P GP IEEE IEEE TI The relationship between Ground Data systems and flight operations for the Aura project TES instrument SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB While Ground Data systems are normally thought of primarily in terms of processors of Science and Calibration data. they are also used by Instrument Operations teams. This paper briefly outlines Aura's Tropospheric Emission Spectrometer (TES) experiment and TES Instrument Operations activities. It describes the data used to trend the health, status, and performance of the TES instrument. which are routed to the TES Instrument Operations Team (IOT) by the Ground Data system.. TES is atypical in that it has some engineering data that are available only in the high rate data stream, rather than in low-rate engineering data. Blocks of commands to perform anticipated TES tasks were developed in parallel with TES flight software design. This paper concludes by showing how this early development of command blocks permitted significantly more flexibility in resolving a variety of TES Operations issues. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Tyler, SR (reprint author), Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1611 EP 1624 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700168 ER PT S AU Morrison, BA AF Morrison, BA GP IEEE IEEE TI Integrated tools and techniques applied to the TES Ground Data system SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Tropospheric Emission Spectrometer (TES) is a Fourier Transform Spectrometer (FTS) scheduled for launch in June of 2003. Over its six-year mission, it is expected to provide three-dimensional maps of ozone and its precursors as part of NASA's Earth Observing System (EOS). Developing production-quality software to process large volumes of scientific data and accommodate changing requirements throughout the mission along with the need to ensure that scientific goals and objectives are met presents many challenges. The author of the paper will discuss the selection of CASE tools, a decision making process, requirements tracking and a review mechanism that leads to a highly integrated approach to software development that must deal with the constant pressure to change software requirements and design that is associated with research and development. This integrated approach of tools and techniques should provide a process and mechanism to assist in continually verifying that mission objectives are correctly expressed in software requirements and fully realized in design in order to achieve overall mission success of the ground data processing system. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Morrison, BA (reprint author), Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1625 EP 1631 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700169 ER PT S AU Watson, SH Thobhani, AB Chan, BB AF Watson, SH Thobhani, AB Chan, BB GP IEEE IEEE TI Design and implementation of the TES Science Data Processing Framework SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Tropospheric Emission Spectrometer (TES) Science Data Processing System (SDPS) is being designed and implemented using a Framework to encapsulate common components, provide abstract interfaces to hardware-dependent features, increase maintainability and greatly reduce the burden on science algorithm development teams. The requirements and architectural design of the TES SDPS Framework were initially presented at the IEEE Aerospace 2000 conference in A Framework-Based Approach to Science Software Development [1]. This paper reviews the Framework, outlines the detailed designs derived from the architectural design, and discusses the major components which have been implemented to date. We also discuss various tools and techniques used during implementation, including our extensive use of the Unified Modeling Language (UML), round-trip engineering, and the inclusion of 3(rd)-party software libraries. Finally, we present our observations on the processes and results to date, and our near- and long-term future plans and goals for the TES SDPS Framework. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Watson, SH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 169-315, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1633 EP 1644 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700170 ER PT S AU Poosti, SH AF Poosti, SH GP IEEE IEEE TI Strategy builder software for atmospheric retrievals SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB This paper introduces the concept of using a Strategy Builder object to automate selection of initial parameters needed to perform an atmospheric retrieval for the Tropospheric Emission Spectrometer (TES) data processing system. Atmospheric retrievals consist of scientific algorithms used to ascertain the actual state of the atmosphere in terms of its temperature and chemical constituents. Atmospheric retrieval algorithms are computationally expensive and convergence of the retrieval is sensitive to input, therefore it is important to provide the best input that will result in the best atmospheric profile. TES has complex requirements in terms of the variety of input data and observations. So it requires a sophisticated system such as Strategy Builder to automate the selection of the optimum strategy for performing the retrieval algorithm on its various types of observation. Strategy Builder also increases the lifetime of the retrieval software by improving its flexibility in implementing various research approaches. Strategy Builder software uses strategy selection logic based on specific strategy selection rules for retrieval of various target scenes. This paper also addresses the issues involved in retrieving the atmosphere of one target scene in a sequence of retrievals. With the robustness that Strategy Builder provides the retrieval software can be used for a longer time, for more research and the produced output is more reliable. It also mitigates the needs for development of extra software for trying different ideas in research. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Poosti, SH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1645 EP 1657 PG 13 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700171 ER PT S AU Wright, JR AF Wright, JR GP IEEE IEEE TI Science data visualization tools for the Tropospheric Emission Spectrometer Ground Data system SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Tropospheric Emission Spectrometer (TES) instrument seeks to analyze the chemical composition of the atmosphere based on the emssion. absorption, and transmission of infrared radiation. Meeting the scientific objectives requires demanding analysis of the data being collected and processed. Visualization tools will assist in the understanding of the data and of the effects of the various types of processing being performed. The TES visualization tools are designed to verify correct functioning of the instrument, provide early detection of potential problems, and report on the quality and validity of the science data for drawing scientific conclusions. Visualization displays include the Level III tools for displaying the end result of all the processing, merged and georeferenced for display relative to maps or global images, and displays for characterizing the behavior of the science processing algorithms and exploring the effects of implementation decisions. Displays of interest include plots of spectra and profiles, animations showing variations in the data along spatial or temporal axes, and results of various operations on the data. Together, these tools provide a visualization suite for more rapidly analyzing the science results of the TES instrument and detecting and identifying problems in the instrument or processing system. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wright, JR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1659 EP 1666 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700172 ER PT S AU Aumann, HH Strow, L AF Aumann, HH Strow, L GP IEEE IEEE TI AIRS, the first hyper-spectral Infrared Sounder for operational weather forecasting. SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB AIRS, the Atmospheric Infrared Sounder on the EOS-Aqua, is an infrared radiometer that covers the 3.7 - 15.4 micron spectral range with spectral resolving power of 1200. AIRS is a cross-track scanner with 15 km nadir footprints, which produces global high precision spectra twice each day from 708 km orbital altitude. In addition to supporting NASA's interest in process study and climate research, AIRS is the first hyper-spectral infrared radiometer designed to support the requirements for operational medium range weather forecasting during its nominal seven year lifetime. AIRS, together with the AMSU and HSB microwave radiometers, are designed to achieve global retrieval accuracy of better then IK rms in the lower troposphere under clear and partly cloudy conditions. Based on the excellent radiometric and spectral performance demonstrated during the pre-launch testing, we expect the assimilation of AIRS data into the forecast model to result in major forecast improvements. We present highlights of the AIRS pre-launch characterization results and concepts for ground data processing using direct retrieval and direct assimilation. Launch of AIRS on the EOS AQUA is scheduled for July, 2001. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Aumann, HH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 3 Z9 3 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1683 EP 1692 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700174 ER PT S AU Pougatchev, NS Smith, WL Harrison, FW Larar, AM Rinsland, CP Jacob, DJ Bey, I Field, BD Yantosca, RM Huang, A Nolf, SR Kireev, SV AF Pougatchev, NS Smith, WL Harrison, FW Larar, AM Rinsland, CP Jacob, DJ Bey, I Field, BD Yantosca, RM Huang, A Nolf, SR Kireev, SV GP IEEE IEEE TI Imaging Geostationary Fourier Transform Spectrometer - Revolutionary tool for tropospheric chemistry SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Geostationary Imaging Fourier Transform Spectrometer (GIFTS) has been selected by the National Aeronautics and Space Administration (NASA) for its 2004 New Millennium Program mission. The GIFTS geophysical data products are derived from measurements of atmospheric thermal emission in 2 spectral bands: 685-1130 cm(-1) and 1650-2250 cm(-1). at high spectral resolution (up to 0.3 cm(-1)) on a 4-km spatial grid. Among key data products are vertically-resolved distributions of ozone and carbon monoxide. Vertical resolution attainable is in the range of 3- to 11-km, depending on a target gas and altitude. To evaluate the GIFTS capability for atmospheric chemistry studies, e.g., sources, sinks, transport and transformation of trace gas, simulations of the GIFTS observations have been performed. Real aircraft in situ profiles and results of the Harvard 3-D model were used as inputs for the simulations. C1 Christopher Newport Univ, NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Pougatchev, NS (reprint author), Christopher Newport Univ, NASA, Langley Res Ctr, MS 472, Hampton, VA 23681 USA. NR 2 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1713 EP 1717 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700176 ER PT S AU Im, E Durden, SL Wu, CL Livermore, TR AF Im, E Durden, SL Wu, CL Livermore, TR GP IEEE IEEE TI The 94-GHz cloud profiling radar for the CloudSat Mission SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The CloudSat Mission is a new international satellite mission to acquire a global data set of vertical atmospheric cloud structure and its variability. Such data set is expected to provide crucial input to the studies of cloud physics, radiation budget, water distribution in the atmosphere, and to the numerical weather prediction models. The key science instrument aboard the CloudSat satellite is the Cloud Profiling Radar (CPR). CPR is a 94-GHz nadir-looking radar that measures the power backscattered by clouds as a function of distance from the radar. This sensor is expected to provide cloud measurements at a 500-m vertical resolution and a 1.5-km horizontal resolution. CPR will operate in a short-pulse mode and will yield measurements at a minimum detectable sensitivity of -28 dBZ. In this paper, we will present the system design and the expected performance of this instrument, as well as the state-of-the art millimeter-wave technologies employed by this instrument. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Im, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1803 EP 1809 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700186 ER PT S AU Sadowy, G Berkun, A Durden, S Huang, J Im, E Lopez, B Lou, M Rahmat-Samii, Y Liu, FY Rengarajan, S AF Sadowy, G Berkun, A Durden, S Huang, J Im, E Lopez, B Lou, M Rahmat-Samii, Y Liu, FY Rengarajan, S GP IEEE IEEE TI Technologies for the next generation of spaceborne precipitation radars SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID RAIN AB The precipitation radar (PR) aboard the Tropical Rainfall Measuring Mission (TRMM) has demonstrated the feasibility of measuring rainfall from space. A concept for the next step, the Second Generation Precipitation Radar (PR-2), has been developed. The PR-2 will yield improved capabilities and substantially reduced system mass compared to the TRMM PR. However, implementation of the PR-2 concept depends upon the development of several technologies including membrane antennas with inflatable structure, Ka-band phased arrays and real time digital pulse compression. Development is currently underway in these areas. This paper surveys the technologies for the PR-2 and describes developments in each aforementioned area. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sadowy, G (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 300-241, Pasadena, CA 91109 USA. NR 4 TC 5 Z9 5 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1811 EP 1823 PG 13 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700187 ER PT S AU Huddleston, JN Spencer, MW AF Huddleston, JN Spencer, MW GP IEEE IEEE TI SeaWinds: The QuikSCAT wind scatterometer SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID PENCIL-BEAM SCATTEROMETER; SATELLITE AB The QuikSCAT wind scatterometer, named SeaWinds, is a scanning, pencil-beam, microwave radar that was designed to measure global ocean surface winds from space. Originally planned for flight aboard the National Space Development Agency of Japan (NASDA) Advanced Earth Observing Satellite II (ADEOS-II) spacecraft, SeaWinds was expected to continue the series of Ku-band scatterometer data initiated by the NASA Scatterometer (NSCAT). Unfortunately, the failure of NSCAT's host spacecraft, ADEOS-I, prematurely ended NSCAT's mission and created a data gap, The QuikSCAT mission was rapidly developed to fill in the data gap between NSCAT on ADEOS-I and SeaWinds on ADEOS-II A scatterometer nearly identical to SeaWinds was quickly assembled and launched on June 19, 1999 aboard the QuikSCAT spacecraft. In this paper, we describe the QuikSCAT mission, outline the key design features of the SeaWinds scatterometer, and mention some of the current and emerging science applications. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Huddleston, JN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 300-319, Pasadena, CA 91109 USA. NR 8 TC 1 Z9 1 U1 2 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1825 EP 1831 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700188 ER PT S AU Spencer, MW Huddleston, JN Stiles, BW AF Spencer, MW Huddleston, JN Stiles, BW GP IEEE IEEE TI Advanced design concepts for a SeaWinds scatterometer follow-on mission SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID OCEAN AB The SeaWinds wind scatterometer was first launched in June of 1999, and has contributed significantly to the study of global climate phenomena and to the fidelity of operational weather forecasting. A second SeaWinds instrument is planned to be launched aboard the Japanese ADEOS-II platform in late 2001, and operate until mid-decade. To extend the important Ku-Band scatterometer data base to the end of the decade and beyond, a follow-on system to the SeaWinds series of scatterometers is being developed. The goals for this system are to continue the core Ku-Band backscatter measurement, to further improve spacecraft accommodation constraints so as to be easily operated on a variety of platforms, and -- where possible under existing cost constraints -- improve wind retrieval performance. It is shown that a system, which meets these objectives, can be achieved by the addition of polarimetric measurement capability to the existing SeaWinds approach. Polarimetric scatterometry is demonstrated to improve wind measurement performance without impacting instrument complexity or cost, and has the long term potential to further ease spacecraft accommodation requirements. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Spencer, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 300-319, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1833 EP 1839 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700189 ER PT S AU Njoku, E Kim, Y Spencer, M Tsai, WY Wilson, B Yueh, S van Zyl, J Rahmat-Samii, Y Thomson, MW AF Njoku, E Kim, Y Spencer, M Tsai, WY Wilson, B Yueh, S van Zyl, J Rahmat-Samii, Y Thomson, MW GP IEEE IEEE TI A spaceborne L-band radiometer-radar concept for land and ocean surface monitoring SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID MICROWAVE AB An L-band radiometer-radar concept has been studied for spaceborne remote sensing of land surface soil moisture, freeze-thaw state, and ocean surface salinity. The integrated design provides simultaneous passive and active measurements with potential for enhanced geophysical retrieval accuracy and spatial resolution. The design takes advantage of cost savings achievable using shared subsystems and hardware. The baseline system concept has been evaluated to determine the feasibility of the technical approach and as a point of departure for system trade-offs. The unique features of this concept are the integration of the radiometer and radar sensors, the use of a deployable-mesh conically scanned reflector antenna, and the use of unfocused synthetic aperture radar (SAR) processing. Taken together, these features represent a significant departure from conventional radiometer, scatterometer, and SAR approaches. The conical wide-swath scan is a desirable feature that provides constant incidence angle and antenna pattern characteristics across the swath, simplified data processing (passive and active), and frequent global sampling. The concept is targeted for a low-cost, short-development-cycle mission, suitable for NASA's Earth System Science Pathfinder (ESSP) series. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Njoku, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1841 EP 1848 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700190 ER PT S AU Tanner, AB AF Tanner, AB GP IEEE IEEE TI A high stability ka-band radiometer for tropospheric water vapor measurements SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The design of two new high stability microwave water vapor radiometers is presented along with a performance evaluation. The radiometers operate next to a spacecraft tracking station at NASA's Goldstone facility in California where they will be used to calibrate tropospheric path delay fluctuations during an upcoming gravity wave search experiment (GWE) involving the Cassini spacecraft. Observing frequencies of the radiometers are 22.2 GHz, 23.8 GHz, and 31.4 GHz, and the antenna beamwidth is 1 degree. The instruments are room temperature Dicke radiometers with additive noise injection for gain calibration. Design highlights include: (1) a practical temperature control system capable of stabilizing the entire receiver to a few millikelvin from day to night; (2) redundant noise diode injection circuits with 30 parts per million RF power stability. and (3) a voice coil actuated waveguide vane attenuator which is used as a high performance Dicke switch. Performance of the radiometers is evaluated from inter-comparisons of the two radiometers and from continuous tip-curve calibrations spanning nearly one year. Structure function analysis of the intercomparison data indicates that the brightness temperature stability of these radiometers is better than 0.01 Kelvin on 1,000 to 10,000 second time scales. Analysis of tip-curve calibrations indicate RMS errors of approximately 0.05 K on 30-day time scales, and 0.15K on one year time scales. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tanner, AB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 3 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1849 EP 1863 PG 15 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700191 ER PT S AU Leisawitz, D Danchi, W DiPirro, M Feinberg, LD Gezari, D Hagopian, M Mather, JC Moseley, SH Silverberg, RF Staguhn, J Zhang, XL AF Leisawitz, D Danchi, W DiPirro, M Feinberg, LD Gezari, D Hagopian, M Mather, JC Moseley, SH Silverberg, RF Staguhn, J Zhang, XL GP IEEE IEEE TI Far-IR/submillimeter space interferometry: Scientific motivation and technology requirements SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID BACKGROUND EXPERIMENT SEARCH; FIRAS AB Far infrared interferometers in space would enable extraordinary measurements of die early universe, the formation of galaxies, stars, and planets, and would have great discovery potential. Half the luminosity of the universe and 98% of the photons released since the Big Bang appear at far-IR and submillimeter wavelengths (40 to 500 mum). Because the Earth's atmosphere prevents sensitive observations from the ground at wavelengths shorter than about 300 mum. and large effective apertures are required to achieve sub-arcsecond angular resolution, this is one of the last unexplored frontiers of observational astronomy. We present the engineering and technology requirements that stem from a set of compelling scientific goals and discuss possible configurations for two proposed NASA missions, the Space Infrared Interferometric Telescope (SPIRIT) and the Submillimeter Probe of the Evolution of Cosmic Structure (SPECS). C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leisawitz, D (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 1995 EP 2004 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700204 ER PT S AU Lawson, PR AF Lawson, PR GP IEEE IEEE TI The Terrestrial Planet Finder SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID NULLING INTERFEROMETER; PHASE-MASK; SPACE; CORONAGRAPH; SEARCH AB The Terrestrial Planet Finder (TPF) is a space-based astronomical telescope that will combine high sensitivity and spatial resolution to detect and characterize similar to 150 planetary systems within 15 pc of our Sun. In a five-year mission. currently expected to commence in 2012, TPF will look for the atmospheric signatures of life using the methods of planetary spectroscopy. This is only possible if implemented within a telescope or interferometer whose spatial resolution is capable of resolving the planet as distinct from its parent star, and yet being able to suppress the starlight to a level of 10(-6) or better. The design of TPF that had been used to illustrate the feasibility of the mission was an interferometer composed of a four-element linear array of 3.5-m diameter telescopes situated in an orbit at L2 and observing over the spectral band of 3-30 microns. At these wavelengths an earth-like planet would be more easily detectable in the glare of the parent star, but the angular resolution required for planet detection implies telescope separations of between 75 and 200 in. and separations of up to 1000 in would be needed for general astrophysics. The interferometer had therefore been envisaged as an array of free-flying telescopes. More recent design studies for TPF have also considered the possibility of having it built as a single-aperture optical telescope. The required angular resolution for planet detection could then be achieved with a mirror spanning 8 or 10 in in diameter. Possible designs include coronagraphs with circular, square. rectangular, or other shaped entry pupils, with tapered transmission across the pupil to suppress unwanted sidelobes in the diffraction pattern. Coronagraphs; with phase masks have also been proposed to more efficiently suppress starlight. For these coronagraphs the principal challenges include not only the suppression of scattered light but the design of adaptive optics systems with sub-nm control. The design requirements and the current status of research will be reviewed. TPF is a key element in NASA's Origins Program and is currently under study in its Pre-Project Phase. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lawson, PR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove, Pasadena, CA 91109 USA. NR 19 TC 11 Z9 11 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2005 EP 2011 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700205 ER PT S AU Velusamy, T Beichman, CA AF Velusamy, T Beichman, CA GP IEEE IEEE TI Nulling interferometry for extra-solar planet detection: Sensitivity & image reconstruction SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID FINDER AB A typical star is more than a million (in infrared) to a billion (in optical) times brighter than a planet. As a result, without special efforts to suppress the starlight, a planet is undetectable in the star's glare. Nulling interferometers. suppress starlight by pointing a null in the interference fringe pattern on the star while pointing a fringe maximum in the direction of the planet. Images of planetary systems are not formed by direct imaging; instead, these images are reconstructed after measurements have been made with the array in multiple orientations and configurations. This paper addresses the image reconstruction issues for nulling interferometer arrays and the sensitivities for planet detection. Nulling interferometers operating in I AU orbit with four 3.5-m telescopes can both detect Earth-like planets at distances as far as 15 parsec and characterize the planet's atmospheric emission for biosignatures. Smaller versions of the nulling interferometer arrays will have the potential to study the giant planets around nearby stars. A 3-element nulling interferometer with telescope sizes 0.5 in - 1 in, on 20 in baseline will have the sensitivity to study Jupiters up to 10 parsec with a few hours integration and to detect earth-size planets at 6 parsec with longer integration of 2 days. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Velusamy, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2013 EP 2025 PG 13 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700206 ER PT S AU Serabyn, E Martin, SR Hardy, GJ AF Serabyn, E Martin, SR Hardy, GJ GP IEEE IEEE TI Progress toward space-based nulling interferometry: Comparison of null stabilization approaches SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID LIGHT; DEEP AB Nulling interferometry is a technique, which can potentially enable the direct detection of light from planets orbiting around nearby stars. In this approach, the light from two or more telescopes is combined using achromatic destructive interference, so that the bright stellar signal incident along the optical axis is canceled. The radiation from fainter off-axis sources is thus left more amenable to detection. Deep nulling of broadband thermal white light has now been demonstrated experimentally at the Jet Propulsion Laboratory [1]. and two different methods of stabilizing the interferometer at the mill-fringe position have been successfully exploited. In this report, the two null-fringe stabilization approaches investigated in our experiments are compared on a theoretical basis, and laboratory results obtained with both stabilization approaches are presented. Finally, a brief status update on current performance levels is provided. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Serabyn, E (reprint author), CALTECH, Jet Prop Lab, Mail Stop 171-113,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2027 EP 2036 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700207 ER PT S AU Duren, RM Liebe, CC AF Duren, RM Liebe, CC GP IEEE IEEE TI The SRTM sub-arcecond metrology camera SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB To achieve the necessary interferometric baseline for the recent Shuttle Radar Topography Mission (SRTM). an outboard radar antenna was deployed using a 60 meter mast from a main radar antenna in the shuttle payload bay. The mast had dominant flexible modes around 0.1 Hz with tip displacements on the order of several centimeters in response to shuttle thrusters. Continuous knowledge of the mast tip position to submillimeter accuracy and antenna orientation to an accuracy of 100 arcseconds (1.6 sigma) was necessary to meet the fundamental SRTM requirements. The selected approach involved an optical metrology camera which tracked three LED targets located on the outboard antenna structure. The metrology camera was required to generate target centroid coordinates (in CCD frame),with a relative accuracy of 0.8 arcsec, I sigma. This paper provides a description of the metrology camera, the process used to prepare it for flight on SRTM, the LED target development effort, test and alignment issues. and the observed in-flight performance. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Duren, RM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2037 EP 2046 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700208 ER PT S AU Cox, B Danesh, P Konefat, EH AF Cox, B Danesh, P Konefat, EH GP IEEE IEEE TI Converting from a lab experiment to a flight instrument SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB This paper describes Instrument Control Electronics (ICE) for the StarLight mission. The mission is a dual-spacecraft formation-flying Michelson interferometer designed to perform the first long-baseline optical interferometry in space. StarLight is planned for launch in late 2005, and will demonstrate enabling technologies in the areas of separated spacecraft control systems. precise optical pathlength control, and interspacecraft laser metrology, all of which are critical to the performance of future planned NASA missions such as the Terrestrial Planet Finder. The interferometer flight instrument is based on a laboratory instrument that been developed over the past ten years. The flight instrument is planning maximum use of the developed hardware and software. There are many challenges in designing flight equivalent instrument electronics that's rugged, lower mass, lower power and reliable. This paper describes the methods. approaches and processes that are being used to design instrument electronics that will meet the project requirements for cost, mass, power and performance. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cox, B (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2057 EP 2065 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700210 ER PT S AU Laskin, RA AF Laskin, RA GP IEEE IEEE TI Technology development for the space interferometry mission (SIM) - Status and plans SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc DE interferometry; metrology; pointing; control; nanometer; picometer; optics; lasers ID SPATIAL INTERFEROMETRY; METROLOGY AB Optical and infrared interferometry will open new vistas for astronomy over the next decade. Space based interferometers, operating unfettered by the Earth's atmosphere, will offer the greatest scientific payoff. They also present the greatest technological challenge: laser metrology systems must perform with sub-nanometer precision; mechanical vibrations must be controlled to nanometers requiring orders of magnitude disturbance rejection, a multitude of actuators and sensors must operate flawlessly and in concert. The Jet Propulsion Laboratory along with its industry partners, LMA and TRW, are addressing these challenges with a development program that plans to establish technology readiness for the Space Interferometry Mission by end of 2003. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Laskin, RA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 73 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2067 EP 2082 PG 16 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700211 ER PT S AU Wette, M AF Wette, M GP IEEE IEEE TI Real-time command, data and control concepts for the instrument on the space interferometry mission SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Space Interferometry Mission (SIM), slated to launch in 2008, will require simultaneous operation of tens of control loops running at kiloHertz rates. The task of designing a computer control system to run this complex, distributed system will require careful requirements analysis and design flow. Though the project is in early phases, the process to flow the flight system command, data, and control system requirements to the instrument real-time control design is well along. In this paper we give a glimpse into the process and resulting design. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wette, M (reprint author), CALTECH, Jet Prop Lab, M-S 198-326,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2083 EP 2087 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700212 ER PT S AU Milman, M Basinger, S AF Milman, M Basinger, S GP IEEE IEEE TI White light fringe estimation: Algorithms, error sources and mitigation strategies SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID PALOMAR TESTBED INTERFEROMETER AB This paper addresses the problem of highly accurate, phase estimation at low light levels, as required by the Space Interferometry Mission (SIM). Most conventional phase estimation algorithms exhibit significant bias at the signal levels and requirements at which SIM will be operating. Several algorithms are analyzed, and methods for compensating for their bias are developed. Another source of error in phase estimation occurs because the phase is not constant over the integration period. Errors due to spacecraft motion, motion of compensating optical elements, and modulation errors are analyzed and simulated. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Milman, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2103 EP 2111 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700214 ER PT S AU Bachmann, A Clark, D Lux, J Steffke, R AF Bachmann, A Clark, D Lux, J Steffke, R GP IEEE IEEE TI Multiprocessor Digital Signal Processing on Earth orbiting scatterometers SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The implementation of a Multi Digital Signal Processor for radar return analysis on a Ku-Band Earth orbiting scatterometer is discussed. Historically, radar signal processing on scatterometers has been implemented with discrete components, Field Programmable Gate Arrays (FPGA)and Application Specific Integrated Circuits (ASIC). These methods are expensive due to long development times, expensive tools. and their lack of modularity. The system presented in this paper uses a radiation tolerant, space qualified version of a commercial general purpose DSP (ADSP-21020) to perform the radar signal processing functions. This approach allows the use of development tools such as compilers, libraries, evaluation boards and emulators. The presented system uses multiple processors interconnected with IEEE-1355 high-speed links to provide the computational power necessary. Operating systems such as Virtuoso provide core capabilities to facilitate scalability, which is important to accommodate changes in functional or performance requirements that inevitably occur late in the development cycle, or even on orbit. A testbed was assembled using a combination of commercial DSP hardware and spaceflight components to evaluate the proposed multiprocessing approaches. Test results of real-time radar echo processing are presented, as well as proposed designs for future investigation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bachmann, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2241 EP 2248 DI 10.1109/AERO.2001.931182 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700229 ER PT S AU Keymeulen, D Stoica, A Buehler, M Zebulum, R Duong, V AF Keymeulen, D Stoica, A Buehler, M Zebulum, R Duong, V GP IEEE IEEE TI Evolutionary mechanisms for smart on-board adaptive sensing applied to the MECA electrometer SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB In-situ exploration as required for example by missions to comets and planets with unknown environmental conditions, has recently been approached with new ideas, such as the use of biology-inspired mechanisms for hardware sensor adaptation. The application of evolution-inspired formalisms to hardware design and self-configuration lead to the concept of evolvable hardware (EHW). EHW refers to self reconfiguration of electronic hardware by evolutionary/genetic reconfiguration mechanisms. In this paper we describe the initial development of efficient mechanisms for smart on-board adaptive sensing, adaptively controlling the reconfigurable pre-processing analog electronics using evolvable hardware, which will lead to higher quality, lean data. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM didier.keymeulen@jpl.nasa.gov NR 27 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2309 EP 2319 DI 10.1109/AERO.2001.931191 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700237 ER PT S AU Zebulum, R Stoica, A Keymeulen, D AF Zebulum, R Stoica, A Keymeulen, D GP IEEE IEEE TI Experiments on the evolution of Digital to Analog Converters SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Evolvable Hardware (EHW) applications have, so far, encompassed the synthesis of standard analog and digital circuits' building blocks through Genetic Algorithms (GAs). Currently, the research effort in EHW is being driven towards twofold purposes: the synthesis of circuits of medium to high complexity; and the design of reconfigurable architectures that facilitate the system evolvability and on-chip implementation of the evolved circuits. This work addresses these issues by describing the evolution of Digital to Analog Converters (DACs). We investigate the efficiency of the evolutionary system when using different representations and when evolving current and voltage mode circuits. A new techinique based on hierarchical evolution is devised to enhance the evolutionary speed and the design scalability. New methods to increase the competitiveness of the evolved designs are also discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zebulum, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2321 EP 2331 DI 10.1109/AERO.2001.931192 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700238 ER PT S AU Barr, SL Mehta, A AF Barr, SL Mehta, A GP IEEE IEEE TI Dimpled ball grid array qualification testing for space flight applications SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB With smaller and smaller Printed Wiring Board (PWB) form factors. such as CompactPCI((R)), the need for smaller packages with high I/Os has grown significantly. A Jet Propulsion Laboratory/NASA technology and system development program that services various spacecraft missions uses a 3U CompactPCI((R)) form factor. The System Input/Output board requires a large amount of I/Os and has limited area, so conventional packages, such as quad flat packs (QFP) will not fit. Thus, the use of Ball Grid Arrays (BGAs) with much smaller package dimensions than leaded packages were needed to meet area requirements and were evaluated for space flight applications. Since this type of package has not been used in past space Right environments, it was necessary to determine the robustness and reliability of the solder joints. The D-BGAs were qualified by developing assembly, inspection and rework techniques as well as environmental tests. The test article was a printed wiring assembly (PWA) consisting of four daisy chained D-BGA packages. Visual inspection of the outer solder joints and real time X-ray were used to verify solder quality prior to testing. The test article was electrically monitored for shorts and opens at or above 1 mus during all environmental tests. Three environmental tests were conducted: random vibration at 0.2 g(2)/Hz, pyro shock at 2000g for 50 ms, and thermal cycling from -55 degreesC to 100 degreesC for 200 cycles. After testing, Scanning Electron Microscope (SEM) analysis was performed on various D-BGA cross sections to determine the quality of the package-to-board interface. The 472 D-BGA solder attachments passed the above environmental tests meeting the minimum requirements for use on space flight electronics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Barr, SL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 103-106, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2391 EP 2400 DI 10.1109/AERO.2001.931198 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700244 ER PT S AU Rasmussen, RD AF Rasmussen, RD GP IEEE IEEE TI Goal-based fault tolerance for space systems using the mission data system SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB In anticipating in situ exploration and other circumstances With environmental uncertainty, the present model for space system fault tolerance breaks down. The perplexities of fault-tolerant behavior, once confined to infrequent episodes, must now extend to the entire operational model. To address this dilemma we need a unified approach to robust behavior that includes fault tolerance as an intrinsic feature. This requires an approach capable of measuring operators' intent in the light of present circumstances, so that actions are derived by reasoning, not by edict. The Mission Data System (MDS), presently under development by NASA is one realization of this paradigm - part of a larger effort to provide multi-mission flight and ground software for the next generation of deep space systems. This paper describes the MDS approach to fault tolerance, contrasting it with past efforts, and offering motivation for the approach as a general recipe for similar efforts. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rasmussen, RD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2401 EP 2410 DI 10.1109/AERO.2001.931199 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700245 ER PT S AU Johnson, MA Rilee, ML Truszkowski, W AF Johnson, MA Rilee, ML Truszkowski, W GP IEEE IEEE TI Using model-based reasoning for autonomous instrument operation SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Model-based reasoning has been applied as an autonomous control strategy on the Low Energy Neutral Atom (LENA) instrument currently flying onboard the Imager for Magnetosphere-to-Aurora Global Exploration (IMAGE) spacecraft. Explicit models of instrument subsystem responses have been constructed and are used to dynamically adapt the instrument to the spacecraft's environment. These functions are cast as part of a virtual Principal Investigator (VPI) that autonomously monitors and controls the instrument. In the VPI's current implementation, LENA's command uplink volume has been decreased significantly from its previous volume; typically, no uplinks are required for operations. This work demonstrates that a model-based approach can be used to enhance science instrument effectiveness. The components of LENA are common in space science instrumentation, and lessons learned by modeling this system may be applied to other instruments. Future work involves the extension of these methods to cover more aspects of LENA operation and the generalization to other space science instrumentation. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Johnson, MA (reprint author), NASA, Goddard Space Flight Ctr, Code 564, Greenbelt, MD 20771 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2411 EP 2419 DI 10.1109/AERO.2001.931200 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700246 ER PT S AU Rilee, ML Boardsen, SA Bhat, MK Curtis, SA AF Rilee, ML Boardsen, SA Bhat, MK Curtis, SA GP IEEE IEEE TI The effect of faults on plasma particle detector data reduction SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID GENERATION AB Missions in NASA's Solar-Terrestrial Probe line feature challenges such as multiple spacecraft and high data production rates, An important class of scientific instruments that have for years strained against limits on communications are the particle detectors used to measure space plasma density, temperature, and flow. The Plasma Moment Application (PMA) software is being developed for the NASA Remote Exploration & Experimentation (REE) Program's series of Flight Processor Testbeds. REE seeks to enable instrument science teams to move data analyses such as PMA on board the spacecraft thereby reducing communication downlink requirements. Here we describe the PMA for the first time and examine its behavior under single bit faults in its static state. We find that similar to 90% of the faults lead to tolerable behavior, while the remainder cause either program failure or nonsensical results. These results help guide the development of fault tolerant, non-hardened flight/science processors. C1 NASA, Goddard Space Flight Ctr, Emergent ITI, Greenbelt, MD 20770 USA. RP Rilee, ML (reprint author), NASA, Goddard Space Flight Ctr, Emergent ITI, Mailstop 931, Greenbelt, MD 20770 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2427 EP 2433 DI 10.1109/AERO.2001.931202 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700248 ER PT S AU Newell, MA Stern, R Hykes, D Bolotin, G Gregoire, T McCarthy, T Buchanan, C Cozy, S AF Newell, MA Stern, R Hykes, D Bolotin, G Gregoire, T McCarthy, T Buchanan, C Cozy, S GP IEEE IEEE TI Extreme temperature (-170C to +125C) electronics for nanorover operation SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The design of the electronics control and data system for the extreme environment seen by a 1.3Kg, 1666 cubic cm nan ver is presented. The Muses-CN electronics is a low mass, low volume, low power electronics platform that must operate over the -170C to +125C temperature range and a I Astronomical Unit (AU) free space radiation environment. The nanorover electronics is a 2.5 watt system that allows for 0.05 to I MIPS processing power and will control 10 motors for mobility and science instruments. Science measurements include Infrared (IR) and Alpha Xray backscatter (AXS) spectrometers along with an Active Pixel Sensor (APS) camera and robotic telemetry signals. Theoretical basis for a low power electronics system with space and commercial grade electronics parts operating in this temperature range is presented. System and component temperature results along with the unique packaging constraints of the Chip on Board (COB) assembly are also discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Newell, MA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2443 EP 2456 DI 10.1109/AERO.2001.931205 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700250 ER PT S AU Henry, MD Brinza, DE AF Henry, MD Brinza, DE GP IEEE IEEE TI DS1 ion propulsion emissions characterization SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Deep Space One mission is demonstrating the long-duration use of an Ion Propulsion Subsystem (IPS). The NASA Solar Electric Propulsion Technology Applications Readiness Project developed the NSTAR Diagnostics Package (NDP) to monitor the effects of the IPS on the spacecraft environment. The NDP measures contamination, plasma characteristics, electric fields, and magnetic fields. This paper describes the different electrostatic and electromagnetic emissions of the ion engine for each of the thrust levels at which the engine has operated in space and in the test chamber. It shows the E and B fields data from the spectrometer and the associated time domain samples. It identifies the unexpected differences between the engine emissions for different thrust levels. It shows the peculiarities of the transitions from one thrust level to another. And it shows the differences in the space and ground test emissions. Examples of other spacecraft emissions will be shown for comparisons to the ion engine emissions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Henry, MD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2505 EP 2513 DI 10.1109/AERO.2001.931211 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700256 ER PT S AU Kortenkamp, D Bonasso, RP Subramanian, D AF Kortenkamp, D Bonasso, RP Subramanian, D GP IEEE IEEE TI Distributed, autonomous control of space habitats SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Long-duration space missions require advanced life support (ALS) systems that can regenerate air, water and food. These ALS systems need complex control strategies that can maintain stable system performance and balance resources with small margins and minimal buffers. In this paper we will describe the ALS control task in detail and give some examples of previous control solutions. Then we will look at how machine learning techniques can help create a more adaptive ALS control system. We will examine reinforcement learning and genetic algorithms and their relationship to optimizing resource utilization in an ALS system. Finally, we will present an innovative multistep genetic algorithm that generates control strategies that perform much better than traditional reinforcement learning or traditional genetic algorithms. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Kortenkamp, D (reprint author), NASA, Lyndon B Johnson Space Ctr, ER2, Houston, TX 77058 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2751 EP 2762 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700280 ER PT S AU Torney, SE Ortiz, JN AF Torney, SE Ortiz, JN GP IEEE IEEE TI Operations assistants for the manned space program SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The manned space program is facing many challenges due to the nature of current and future programs. Automation in the form of Operations Assistants is being pursued as a solution to some of these challenges. This paper describes the nature of the challenges and NASA / Johnson Space Center's approach to meeting these challenges. This includes a description of the initial phase of the Operations Assistant project and the presentation of a staged approach to incorporating intelligent agents. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Torney, SE (reprint author), NASA, Lyndon B Johnson Space Ctr, 2101 NASA Rd 1, Houston, TX 77058 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2763 EP 2773 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700281 ER PT S AU Mandutianu, S Hadaegh, F Elliot, P AF Mandutianu, S Hadaegh, F Elliot, P GP IEEE IEEE TI Multi-agent system for formation flying missions SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Currently, spacecraft are not operated as autonomous coordinated teams. Generalized reasoning capability offered by advanced distributed software technology and Al have the potential to cope with unexpected events and uncertainty and allow to close the loop of perception, decision and eventually deliberation, on board. The team members play different interchangeable roles and they negotiate the task that they are achieving together. We present a multi-agent system to provide a high degree of autonomy and support for coordination among team members. We use JPL formation flying mission initial architectures as benchmark. Our target is to avoid inconsistencies/disagreements between two or more participants in a collaborative context, increase the system's fault tolerance in cases such as loss of a member while the system should be able to still reliably operate. We address the cooperation between independent autonomous agents when they have to collaborate to achieve a common goal. In a top-down organization, agents are coordinated in a hierarchical fashion, where the agents at the top of the hierarchy make the majority of the intelligent group decisions. In a more structured, but still hierarchical organization, lower-level agents exercise more intelligence in making group decisions. A lower-level agent can advance a plan for the others to follow, and then a higher rank agent will decide on the best plans produced by individual agents. Although more rigid, the centralized intelligence organization allows for less communication among agents, so is more straightforward to implement. The decentralized approach requires more communication, but the intelligence is truly distributed, which makes for a more flexible, adaptive and efficient organization. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mandutianu, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 161-260, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2793 EP 2802 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700283 ER PT S AU White, AL AF White, AL GP IEEE IEEE TI Comments on modified condition/decision coverage for software testing SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB This paper considers the Modified Condition/Decision Coverage method of testing software. There is an explanation of the method and why it appears reasonable; the probability model offered as a justification is closely examined; and several experiments are described that check the underlying assumptions of the method and its probability model. The method checks the implementation of Boolean expressions by checking the correctness of certain entries in the truth table. These entries are the ones for which a change in a single variable changes the evaluation of the entire expression. The probability model offered as a justification, however, is shown to be equivalent to a binomial distribution of errors, which says all entries are equally likely to be incorrect. Hence, there is not a match between the method and the model. For this reason, a number of experiments are proposed to test the assumptions of the method and the model. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP White, AL (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 3 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2821 EP 2827 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700286 ER PT S AU Semmel, G Walton, GH AF Semmel, G Walton, GH GP IEEE IEEE TI Developing and validating thousands of executable finite state machines SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID MODEL CHECKING; REQUIREMENTS SPECIFICATIONS; SPIN AB In 1996, a project began at NASA's Kennedy Space Center to replace the legacy Launch Processing System with a state-of-the-art process control system called the Checkout and Launch Control System. Over 13 million lines of real time control software are being reengineered from a legacy language called Ground Operations Aerospace Language to a modem graphical programming language called ControlShell by Real Time Innovations. ControlShell combines a graphical language with a component-based design methodology. The ControlShell finite state machine component type is semantically similar to the statecharts of the Unified Modeling Language (UML). Thousands of executable finite state machines are being developed for the new launch system. The new system must deliver exceptionally reliable software to maintain safe operations and a high level of confidence by the end users. This paper discusses some of the development challenges of this project, the design approach, and the use of automated model checking for validation. C1 NASA, Kennedy Space Ctr, FL 32899 USA. RP NASA, YA E1-S3, Kennedy Space Ctr, FL 32899 USA. EM glenn.semmel-l@ksc.nasa.gov; gwalton@mail.ucf.edu NR 22 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2837 EP 2848 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700288 ER PT S AU Hall, L Hung, C Hwang, C Oyake, A Yin, J AF Hall, L Hung, C Hwang, C Oyake, A Yin, J GP IEEE IEEE TI COTS-based OO-component approach for software inter-operability and reuse (Software systems engineering methodology) SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The purpose of this research and study paper is to provide a summary description and results of rapid development accomplishments at NASA/JPL in the area of advanced distributed computing technology using a Commercial-Off-The-Shelf(COTS)-based object-oriented component approach to open inter-operable software systems development and software reuse (i.e., COTS-based software components in action). Distributed COTS middleware (such as CORBA ACETAO) coupled with a well-defined layered software architecture can be used to support infrastructure development for object-oriented component technology. It can provide a framework for component development, legacy incorporation, and reuse and inter-operability across subsystems. With detailed systems engineering, it can reduce development, testing, and maintenance relative to life-cycle cost and time. This paper will 1) address what is meant by the terminology object-oriented (OO) component software and how object component technology can be used in scientific software development and operational environments, 2) give an overview of the component-based implementation strategy and how it relates to infrastructure support of software architectures promoting reuse/inter-operability, and 3) evaluate the benefits or lessons learned from this approach (such as complexity of integration and avoiding duplication or re-development efforts). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hall, L (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 2 Z9 2 U1 1 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2871 EP 2878 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700292 ER PT S AU Filman, RE AF Filman, RE GP IEEE IEEE TI A software architecture for intelligent synthesis environments SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB NASA's Intelligent Synthesis Environment (ISE) program is a grand attempt to develop a system to transform the way complex artifacts are engineered. This paper discusses a "middleware" architecture for enabling the development of ISE. Desirable elements of such an Intelligent Synthesis Architecture (ISA) include remote invocation; plug-and-play applications; scripting of applications, management of design artifacts, tools, and artifact and tool attributes: common system services; system management; and systematic enforcement of policies. A typical middleware foundation for an ISA is a distributed object technology such as CORBA (Common Object Request Broker Architecture). I argue that such an architecture can be profitably extended by enabling "plug-and-play" insertion of new policies into the system. I describe the Object Infrastructure Framework. an Aspect Oriented Programming (AOP) environment for developing distributed systems that provides policy insertion. This technology can be used to enforce policies such as maintaining the annotations of artifacts, particularly the provenance and access control rules of artifacts, performing automatic datatype transformations between representations; supplying alternative servers of the same service; reporting on the status of jobs and of the system, conveying privileges throughout an application; supporting long-lived transactions; maintaining version consistency; and providing software redundancy and mobility. C1 NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Moffett Field, CA 94035 USA. RP Filman, RE (reprint author), NASA, Ames Res Ctr, Adv Comp Sci Res Inst, MS 269-2, Moffett Field, CA 94035 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2879 EP 2887 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700293 ER PT S AU Weidner, R AF Weidner, R GP IEEE IEEE TI A component based implementation of agents and brokers for design coordination SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB NASA's mission design coordination has been based on expert opinion of parametric data presented in Excel or PowerPoint. Common access is required to more powerful design tools supporting performance simulation and analysis. Components provide the means for inexpensively adding the desired functionality,. An information exchange was developed to provide the physical models required to perform performance analysis of mission designs. The exchange product is continuous polymorphic model data over finite time intervals. Using Distributed Component Object Model (DCOM) components, information brokers were developed to provide controlled access to the products. Each access is a persistent contextual transaction specific to a design team. Information agent Dynamic Link Libraries (DLLs) were developed to translate information requests, search among the brokers, retrieve the exchange products and ultimately generate high level model information such as state or attitude. An in-process dual component interface was developed to provide direct access from off-ice productivity tools to the agent DLLs. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Weidner, R (reprint author), CALTECH, Jet Prop Lab, MS 168-522,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2889 EP 2895 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700294 ER PT S AU Mackey, R James, M Park, H Zak, M AF Mackey, R James, M Park, H Zak, M GP IEEE IEEE TI BEAM: Technology for autonomous self-analysis SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB BEAM (Beacon-based Exception Analysis for Multimissions) is an end-to-end method of data analysis intended for real-time fault detection and characterization. It provides a genetic system analysis capability for potential application to deep space probes and other highly automated systems. This paper describes in brief the architecture, application, and operating theory of BEAM. We will also make reference to companion papers [1] and [2]. which describe individual elements of the technology in mathematical detail. BEAM provides a generalized formalism for diagnostics and prognostics in virtually any instrumented system. Consideration is given to all standard forms of data, both time-varying (sensor or extracted feature) quantities and discrete measurements, embedded physical and symbolic models, and communication with other autonomy-enabling components such as planners and schedulers. This approach can be adapted to on-board or ground-based implementations with no change to the basic operating theory. The approach will be illustrated with an overview of application types, past validations, and ongoing efforts. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mackey, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 126-147, Pasadena, CA 91109 USA. NR 9 TC 5 Z9 5 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 2989 EP 3001 PG 13 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700303 ER PT S AU Hambaba, A Huff, E Kaul, U AF Hambaba, A Huff, E Kaul, U GP IEEE IEEE TI Time-scale local approach for vibration monitoring SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB It is difficult to monitor machine condition and diagnose mechanical faults in mechanical equipment which have varied operational modes and whose dynamic signals are nonstationary. The identification of natural frequencies of vibration and modal damping is of fundamental engineering importance. The damage done to a particular structure under an unknown force might be ascribed to the relative damping or the lack thereof and the natural frequencies of a vibrating system. The paper focuses on the design of a fault detection algorithm, which consists of two steps: (1) residual generation at each scale and (2) decision rules. The designed residual measurements are to reflect possible changes of interest in the dynamic signal. They are based on sufficient statistics of the model parameters at each resolution level. The decision rule is based on the generated residual. The following decision mechanisms are implemented: chi-squared test, and Shewhart control chart. The vibrating system that is considered in this research, is the gear dynamic system. The dynamic system considered in this research is a vibrating gear system. C1 NASA, Ames Res Ctr, NRC, Moffett Field, CA 94035 USA. RP Hambaba, A (reprint author), NASA, Ames Res Ctr, NRC, MS 269-1, Moffett Field, CA 94035 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3201 EP 3209 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700320 ER PT S AU Hambaba, A Huff, E Kaul, U AF Hambaba, A Huff, E Kaul, U GP IEEE IEEE TI Detection and diagnosis of changes in the time-scale eigenstructure for vibrating systems SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The paper focuses on techniques used in monitoring machine condition and diagnosing mechanical faults in vibrating mechanical equipment which have varied operational modes and whose dynamic signals are nonstationary. Because of the nonstationary nature of the vibrating system, one has to apply the time-scale transform to capture the nonstationary modes. The autoregressive moving average modeling captures the modal signatures, in particular. the autoregressive components (natural frequencies and damping in various modes) of the vibrating system. We consider the problem of detecting and diagnosing changes in the eigenstructure of the state transition matrix of the state-space model. A chi-square test is performed at different level of resolution in the time-scale space. The dynamic system that is considered in this research is a vibrating gear system. C1 NASA, Ames Res Ctr, NRC, Moffett Field, CA 94035 USA. RP Hambaba, A (reprint author), NASA, Ames Res Ctr, NRC, MS 369-1, Moffett Field, CA 94035 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3211 EP 3220 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700321 ER PT S AU Backes, PG Norris, JS AF Backes, PG Norris, JS GP IEEE IEEE TI Automated Rover sequence report generation SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB A web-based rover mission operations report and its various elements are described. The system was used for documentation of the Field Integrated Design and Operations (FIDO) rover May 2000 field test and results from the field test are provided. Implementation of automated sequence report generation for the operations report is explained in detail. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Backes, PG (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3329 EP 3337 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700332 ER PT S AU Norris, JS Backes, PG Baumgartner, ET AF Norris, JS Backes, PG Baumgartner, ET GP IEEE IEEE TI PTEP: The parallel telemetry processor SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Parallel Telemetry Processor (PTEP). a high-speed, robust, and extensible telemetry processing system is discussed in this paper. The system. written in Java. provides a multithreaded task-dispatching framework for downlink processing that allows existing data processing applications to be easily integrated into the processing pipeline. The system provides users with a color-coded flowchart that indicates the progress of packets through the system and displays intermediate data products as they are generated. Packets that cause processing errors are stored in an error queue for later review while the system continues to process new packets. PTEP currently processes telemetry from 7 different instruments on the FIDO prototype Mars rover at JPL. including multiple stereo cameras, a spectrometer. and a microscope. PTEP generates 21 science data products (5 megabytes of data) for every stereo image pair taken by the rover. Throughput is approximately 2 packets per minute, making it possible to process an entire downlink from the rover in minutes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Norris, JS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3339 EP 3345 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700333 ER PT S AU Scott, CJ AF Scott, CJ GP IEEE IEEE TI Animated software training via the Internet: Lessons learned SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Mission Execution and Automation Section, Information Technologies and Software Systems Division at the Jet Propulsion Laboratory, recently delivered an animated software training module to train operators at the Deep Space Network for the TMOD UPLINK Consolidation Task. The animated training software was presented as a Command Subsystem simulation for on-line instruction. Animation was developed as a prototype (papers [1][2] describing the initial development of this animation were presented at earlier conferences) and became a design and training tool. From development through delivery, significant animation design changes were made to keep pace with the changing Command formats and techniques being developed for the Deep Space Network, thus enabling training software to remain concurrent with subsystem development. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Scott, CJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr MS 301-270, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3367 EP 3374 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700336 ER PT S AU Bokor, E AF Bokor, E GP IEEE IEEE TI Automating operations for NASA's deep space network (DSN) SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The DSN is the communication gateway to NASA's Earth Orbiting and planetary spacecraft. The DSN is unique among space communication systems in that it is link configurable. For each pass of a spacecraft, there is a set of antennas, receivers. transmitters, and other signal processing subsystems which can be combined to complete a tracking cycle. In the past, when the number of orbiting satellites and planetary spacecraft were fairly small, manual control of this complex tracking system was manageable. However, with the growth in planned missions for Mars, Venus, the sun. outer planets. comet flybys. and asteroid encounters. it is becoming increasingly clear that the complex tasks associated with antenna control/coordination and telemetry capture will eventually overwhelm existing tracking crews. Mistakes in data entry/retrieval can result in loss of valuable science data as well as spacecraft control blackout. This paper describes the DSN automation system design, functions, test results, and actual field implementation experience. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bokor, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3375 EP 3383 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700337 ER PT S AU Smith, JH Wang, YF AF Smith, JH Wang, YF GP IEEE IEEE TI E-scheduling the deep space network SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Anticipated growth in demand for NASA's Deep Space Network (DSN) and its services has created a need to streamline the delivery of telecommunications services. The process for scheduling services is a key component of the interface between mission customers requesting telecommunication support for their spacecraft and DSN providers managing the ground system (antennas). The scheduling process can be viewed as a reservation system for reserving tracking time (known as "tracks") for space missions. The current scheduling process has evolved into a complex, assembly line operation iii which different paper-based, file based, and manual systems are used to pass the schedule between different organizations. A variety of different and often arcane formats of the schedule are maintained in accordance with each organization's needs. As a result, mission customers are confronted with a complicated process requiring high levels of direct communication (phone, facsimile, email) and extensive conflict resolution meetings. As tracking reservations approach real-time operation, it is common for last minute schedule changes to require significant rework and new data support products while remote DSN Complexes must adapt to the changes. This paper describes an operations concept for electronic scheduling and software interface for organizations to extract required views of the schedule. Advantages include widespread accessibility to a common schedule document, virtually instantaneous distribution of new schedule releases, and the ability of missions to perform conflict resolution off-line without time-consuming meetings, The operations concept and e-scheduling tool are under development and testing for three scheduling organizations within the Telecommunications and Mission Operations Directorate at JPL. Observations relevant to the deployment of an e-scheduling operations concept are described. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Smith, JH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 301-165, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3385 EP 3391 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700338 ER PT S AU Connally, MJ Kuiper, TB AF Connally, MJ Kuiper, TB GP IEEE IEEE TI DSMS science operations concept SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Deep Space Mission System (DSMS) Science Operations Concept describes the vision for facilitating the use of the DSMS, particularly the Deep Space Network (DSN) for direct science observations in the areas of Radio Astronomy. Planetary Radar. Radio Science and VLBI. Scientific research is inherently an innovative activity: the "surprising result" is the best possible outcome. This operations concept establishes a framework that allows scientists to make full use of the DSMS's science capabilities by providing the amount and type of collaboration from DSMS science personnel appropriate to each observation program. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Connally, MJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3407 EP 3411 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700340 ER PT S AU Lee, MM Weidner, RJ Lu, WW AF Lee, MM Weidner, RJ Lu, WW GP IEEE IEEE TI Design-based mission operation SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Virtual Mission project led by the Mission Simulation and Instrument Modeling Group at JPL has been playing an active role hi the NASA-wide information technology infusion programs, such as. Information System Technology. Next-Generation Infrastructure Technology, and Intelligent Synthesis Environment. The goal of the Virtual Mission project is to enable automated design space exploration. progressive design optimization. and lifecycle-wide design validation to ensure mission success. Design-based mission operation has been a major part of the research effort in order to establish system-wide as well as lifecycle-wide impact analysis as an integral part of the mission design process, The design-based mission operation is approached by implementing Virtual Mission Lifecycle (VML), modeling and simulation tools and system engineering processes for building a virtual mission system that can perform a realistic mission operation during the design phase of a mission. As in the real mission lifecycle convention. the VML is composed of design, development, integration and test. and operation phases. This paper describes the four phases of the VML addressing a major challenge per phase. mission model framework, virtual prototyping, agent-based mission system integration, and virtual mission operation. C1 Jet Prop Lab, Pasadena, CA 90272 USA. RP Lee, MM (reprint author), Jet Prop Lab, 4800 Oak Grove, Pasadena, CA 90272 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3429 EP 3441 PG 13 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700343 ER PT S AU White, AL AF White, AL GP IEEE IEEE TI A statistics of rare events method for transportation systems SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB A method is proposed for quantifying the expected number of accidents for a transportation system during some operating period. The operating period is divided into two parts. There is normal operation where everything is working correctly. These intervals can be studied deterministically by arguments-from-design or by tests. There is unsafe operation where equipment has failed, an error has occurred, or traffic perturbations have produced unusual circumstances. Such stochastic phenomena can be studied by experiments or simulation. These two types of operation create a natural partition. This paper proposes a Monte Carlo method based on this partition that appears appropriate for studying scarce events. Estimators for this method are developed. It is shown they are unbiased, and confidence intervals derived. There is also a discussion of integrating random failures with traffic flow in a discrete event simulation. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP White, AL (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3443 EP 3449 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700344 ER PT S AU Pfarr, B Rice, MW Fatig, CC Green, D AF Pfarr, B Rice, MW Fatig, CC Green, D GP IEEE IEEE TI Wearable computers for NASA applications SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB At the Goddard Space Flight Center, members of the Real-Time Software Engineering Branch are developing a wearable. wireless. voice-activated computer using many off-the-shelf components. This will be used in a wide range of crosscutting space applications that would benefit from having instant internet. network, and computer access with complete mobility and hands-free operations. These applications can be applied across many fields and disciplines including spacecraft fabrication, integration and testing (including environmental testing), and astronaut on-orbit control and monitoring of experiments with ground based experimenters. To satisfy the needs of NASA customers, this wearable computer needs to be connected to a Wireless network, to transmit and receive real-time video over the network, and to receive updated documents via the Internet or NASA servers. The voice-activated computer. with a unique vocabulary, will allow the users to access documentation in a hands-free environment and interact in real-time with remote users. We will discuss wearable computer development, hardware and software issues, wireless network limitations, video/audio solutions and difficulties in language development. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pfarr, B (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. RI Pfarr, Barbara/C-6785-2015 NR 6 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3489 EP 3497 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700349 ER PT S AU Jacob, JC Plesea, L AF Jacob, JC Plesea, L GP IEEE IEEE TI Fusion, visualization and analysis framework for large, distributed data sets SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB In this paper a framework is presented for extracting information content from modem sky surveys, which have archived multiple terabytes of data in various wavelengths and at various resolutions. The proposed framework includes new technology that addresses the massive size and geographically distributed nature of these data sets. Also included is automated support for combining data sets from multiple archives and for relating sky catalogs to the image data. In addition. tools are provided for efficiently exploring images that are hundreds of gigabytes or even multiple terabytes in size. The proposed framework and "data agile" applications described here are essential in the modem era of astronomy because images of this size far exceed the current capabilities of conventional image analysis tools used in the astronomical community. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jacob, JC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 126-234, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3523 EP 3530 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700352 ER PT S AU Craig, DA Monell, DW Moore, AA Simpkins, PA AF Craig, DA Monell, DW Moore, AA Simpkins, PA GP IEEE IEEE TI Development and utilization status of NASA's advanced engineering environment - ISE SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Aerospace design processes demand the best talent (regardless of geographic location), with access to the best design and analysis tools to reduce design cycle times and cost without sacrificing reliability or safety. The solution is a collaborative, distributed engineering environment for life-cycle analysis. The National Aeronautics and Space Administration (NASA) is developing such an advanced engineering environment, called the Intelligent Synthesis Environment (ISE). This paper reports the progress made in developing ISE, future development plans and ISE success stories to date. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Craig, DA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 12 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3537 EP 3548 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700354 ER PT S AU Montemerlo, MD AF Montemerlo, MD GP IEEE IEEE TI NASA's Gossamer Spacecraft Technology Program SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc C1 NASA, Washington, DC 20546 USA. RP Montemerlo, MD (reprint author), NASA, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3581 EP 3581 PG 1 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700358 ER PT S AU Moore, CL AF Moore, CL GP IEEE IEEE TI Gossamer spacecraft technology for space solar power systems SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB Gossamer spacecraft technology is critical for enabling large, space-based systems to collect and transmit solar power. This paper gives an overview of structures, materials. and control technology development for space solar power systems. Key technologies include inflatable structures. in-space fabrication of structural elements. robotic assembly. multifunctional structures, active control of flexible structure dynamics, and lightweight radiators. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Moore, CL (reprint author), NASA, Langley Res Ctr, MS 214, Hampton, VA 23681 USA. NR 12 TC 1 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3585 EP 3589 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700360 ER PT S AU Lake, M AF Lake, M GP IEEE IEEE TI Astronaut construction of large aperture structures in space SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Lake, M (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3591 EP 3591 PG 1 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700361 ER PT S AU Chmielewski, A AF Chmielewski, A GP IEEE IEEE TI NASA's large telescope systems initiative SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chmielewski, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3593 EP 3593 PG 1 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700362 ER PT S AU Price, H AF Price, H GP IEEE IEEE TI Solar sail technology at NASA SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Price, H (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3595 EP 3595 PG 1 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700363 ER PT S AU Baggett, R AF Baggett, R GP IEEE IEEE TI Solar sail technology in NASA's advanced spacecraft technology program SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Baggett, R (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3597 EP 3597 PG 1 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700364 ER PT S AU Lake, MS AF Lake, MS GP IEEE IEEE TI Launching a 25-meter space telescope - Are astronauts a key to the next technically logical step after NGST? SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The present study considers architectures for a 25-meter (25m) space telescope mirror that leverage the technology development currently underway for the Next Generation Space Telescope (NGST). Key engineering requirements are derived that distinguish a 25m mirror from the 8m NGST mirror. The feasibility of applying both mirror panel and active-alignment-control technologies currently under development for the NGST to a larger (25m) telescope mirror is discussed. Analyses are presented that indicate it is impractical to mechanically deploy a 25m-telescope mirror simply because of the volumetric packaging inefficiency of such concepts. Instead, it is shown that an erectable mirror, assembled by either astronauts or robotic devices, provides the most logical mirror architecture. Finally, it is shown that an observatory with a 25m primary mirror could be launched in one Shuttle mission for assembly and initial checkout in low Earth orbit. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Lake, MS (reprint author), NASA, Langley Res Ctr, M-S 190, Hampton, VA 23681 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3599 EP 3611 PG 13 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700365 ER PT S AU Folkner, WM Horowitz, S AF Folkner, WM Horowitz, S GP IEEE IEEE TI The Laser Interferometer Space Antenna mission SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc ID LISA AB The Laser Interferometer Space Antenna (LISA) mission is designed to detect and study low-frequency gravitational radiation. The types of exciting astrophysical sources potentially visible to LISA include extra-galactic massive black hole binaries at cosmological distances, binary systems composed of a compact star and a massive black hole, galactic neutron star-black hole binaries, and background radiation from the Big Bang. LISA will also observe galactic binary systems which are known to exist. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Folkner, WM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3613 EP 3619 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700366 ER PT S AU Lambros, S AF Lambros, S GP IEEE IEEE TI Gamma-ray Large Area Space Telescope (GLAST) mission SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Gamma-ray Large Area Space Telescope (GLAST) mission is a scientific spaceflight investigation that measures the direction, energy and arrival time of celestial gamma rays. It is planned for launch in September 2005. The scientific applications include determining the structure of high-energy astrophysical processes such as those found in active galactic nuclei, black holes, and supernovae. Several other natural phenomena in the universe will be investigated. One of the most exciting aspects of the GLAST mission is its potential for new discovery. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Lambros, S (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3621 EP 3628 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700367 ER PT S AU Grady, JF Gadwal, GR AF Grady, JF Gadwal, GR GP IEEE IEEE TI The Constellation X-ray mission: Exploring the mysteries of matter in the Universe SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Constellation-X. a premier observatory for probing black holes and investigating the structure of the Universe, is planned for launch near the end of this decade. This observatory will consist of a constellation of identical space based X-ray telescopes, with a large total collecting area and sensitivity one hundred times previous missions. The current Reference Mission Configuration consists of four satellites. which are launched. two at a time, into operational orbit at the Sun-Earth libration point, L2. Development is currently underway to demonstrate several mission critical technologies including: large lightweight grazing incidence X-ray optics, improved X-ray detectors (microcalotimeters, Charged Coupled Devices and CdZnTe detectors) with sensitivities from 0.25 to 40 kiloelectron volts (keV). sub Kelvin coolers for detectors. lightweight mass producible reflection gratings. and multi-layer coatings for X-rays up to 40 keV. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Grady, JF (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3629 EP 3635 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700368 ER PT S AU White, N Margon, B AF White, N Margon, B GP IEEE IEEE TI NASA Structure and Evolution of the Universe theme: Science overview SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The NASA Office of Space Science Structure and Evolution of the Universe (SEU) theme covers a wide variety of scientific investigations, from the nearest bodies to the farthest observable distances just after the time of the Big Bang. SEU supports experiments that sense radiation of all wavelengths, together with particle and gravitational wave detection. Recently completed road mapping and strategic planning exercises have identified a number of near- and medium-term space initiatives for the 2003-2023 time frame. Each of these experiments pushes the state of the art technically, but will return incredible new insights on the formation and evolution of the universe, as well as probe fundamental laws of physics in regimes never before tested. The scientific goals and technological highlights of each mission are described. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP White, N (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 661, Greenbelt, MD 20771 USA. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3637 EP 3642 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700369 ER PT S AU Carter, RC Collins, CM Eby, R Lewis, R Yun, D Crow, J Robinson, D Branch, H Flatley, T Larsen, R Park, B Tompkins, S Kidd, L Kim, C Budinoff, J AF Carter, RC Collins, CM Eby, R Lewis, R Yun, D Crow, J Robinson, D Branch, H Flatley, T Larsen, R Park, B Tompkins, S Kidd, L Kim, C Budinoff, J GP IEEE IEEE TI ACCESS: Advanced Cosmic-Ray Composition Experiment for the Space Station SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB The Advanced Cosmic-ray Composition Experiment for Space Station (ACCESS) is a space science payload that will be deployed on the International Space Station (ISS). The ACCESS mission will help address the NASA Structure and Evolution of the Universe (SEU) theme's quest "to explore the cycles of matter and energy in the evolving universe." ACCESS utilizes two insitu instruments to study cosmic ray shower events induced in the instruments from the vantage point of the ISS. ACCESS records these events in an energy spectra range between 10(12) and 10(15) eV. This paper describes the end-to-end mission concept design, including flight hardware and mission operations. The flight hardware design addresses the ACCESS science requirements, as well as the interface requirements of the ISS and the launch and landing requirements of the shuttle. The ACCESS flight hardware consists of two science instruments and the Payload Support and Interface Module (PSIM). The PSIM serves as a carrier in the space shuttle cargo bay during launch and landing for transportation to and from the ISS and, thereafter. provides system support to the instruments when the ACCESS payload is mated onto the ISS starboard truss. The on-orbit mission life is 4 years and the mission takes advantage of the inherent capability of the ISS to accommodate large and massive payloads. The ACCESS mission requirements are compatible with the ISS environments and the resources provided by the ISS are suitable for meeting mission orbit objectives. The mission concept design demonstrates the feasibility of the ACCESS mission on the ISS. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Carter, RC (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3643 EP 3654 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700370 ER PT S AU Cooke, DE AF Cooke, DE GP IEEE IEEE TI An overview of NASA's intelligent systems program SO 2001 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-7 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 10-17, 2001 CL BIG SKY, MT SP IEEE Aerosp & Electr Syst Soc AB NASA and the computer science research community are poised to enter a critical era. An era hi which - it seems - each needs the other. Market forces. driven by the immediate economic viability of computer science research results. place computer science in a relatively novel position. These forces impact how research is done. and could. in the worst case. drive the field away from significant innovation - opting instead for incremental advances that result in greater stability in the market place. NASA, however. requires significant advances in computer science research in order to accomplish the exploration and science agenda it has set out for itself. NASA may indeed be poised to advance computer science research in this century, much the way it advanced aero-based research in the last. C1 NASA, Ames Res Ctr, Mt View, CA USA. RP Cooke, DE (reprint author), NASA, Ames Res Ctr, Mt View, CA USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-6599-2 J9 AEROSP CONF PROC PY 2001 BP 3661 EP 3664 PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BT34X UT WOS:000172696700372 ER PT B AU Simon, MK Divsalar, D AF Simon, MK Divsalar, D GP IEEE IEEE TI A reduced complexity highly power/bandwidth efficient coded FQPSK system with iterative decoding SO 2001 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-10, CONFERENCE RECORD LA English DT Proceedings Paper CT IEEE International Conference on Communications CY JUN 11-14, 2001 CL HELSINKI, FINLAND SP IEEE, IEEE Communicat Soc, Globe Com AB Based on a representation of FQPSK as a trellis-coded modulation, this paper investigates the potential improvement in power efficiency obtained from the application of simple (small number of states) outer codes to form a concatenated coding arrangement with iterative decoding. Several possible configurations for the concatenation are suggested and specific numerical results are presented for one of these in order to demonstrate the large coding gains that are achievable even when using a reduced complexity FQPSK receiver. The end result of these investigations is a system which has application in scenarios requiring a high degree of both power and bandwidth efficiency. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Simon, MK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 18 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7097-1 PY 2001 BP 2204 EP 2210 PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BT50Q UT WOS:000173159000418 ER PT B AU Simon, MK Divsalar, D AF Simon, MK Divsalar, D GP IEEE IEEE TI A reduced complexity highly power/bandwidth efficient coded FQPSK system with iterative decoding SO 2001 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-10, CONFERENCE RECORD LA English DT Proceedings Paper CT IEEE International Conference on Communications CY JUN 11-14, 2001 CL HELSINKI, FINLAND SP IEEE, IEEE Communicat Soc, Globe Com AB Based on a representation of FQPSK as a trellis-coded modulation, this paper investigates the potential improvement in power efficiency obtained from the application of simple (small number of states) outer codes to form a concatenated coding arrangement with iterative decoding. Several possible configurations for the concatenation are suggested and specific numerical results are presented for one of these in order to demonstrate the large coding gains that are achievable even when using a reduced complexity FQPSK receiver. The end result of these investigations is a system which has application in scenarios requiring a high degree of both power and bandwidth efficiency. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Simon, MK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 18 TC 0 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7097-1 PY 2001 BP 2963 EP 2969 PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BT50Q UT WOS:000173159000564 ER PT S AU Olson, CF Matthies, LH Schoppers, M Maimone, MW AF Olson, CF Matthies, LH Schoppers, M Maimone, MW GP IEEE IEEE IEEE TI Stereo ego-motion improvements for robust rover navigation SO 2001 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS I-IV, PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 21-26, 2001 CL SEOUL, SOUTH KOREA SP IEEE Robot & Automat Soc, IEEE ID 3-D AB Robust navigation for mobile robots over long distances requires an accurate method for tracking the robot position in the environment. Techniques for position estimation by determining the camera ego-motion from monocular or stereo sequences have been previously described. However, long-distance navigation requires a very high level of robustness and a very low rate of error growth. In this paper, we describe a methodology for long-distance rover navigation that meets these goals using robust estimation. We show that a system based on only camera ego-motion estimates will accumulate errors with super-linear growth in the distance traveled, owing to increasing orientation errors. When an absolute orientation sensor is incorporated, the error growth can be reduced to a linear function of the distance traveled. We have tested these techniques using both extensive simulation and hundreds of real rover images and have achieved a low, linear rate of error growth. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Olson, CF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 36 Z9 39 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-6576-3 J9 IEEE INT CONF ROBOT PY 2001 BP 1099 EP 1104 PG 6 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA BT31J UT WOS:000172615800176 ER PT S AU Tunstel, E Howard, A Seraji, H AF Tunstel, E Howard, A Seraji, H GP IEEE IEEE IEEE TI Fuzzy rule-based reasoning for rover safety and survivability SO 2001 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS I-IV, PROCEEDINGS SE IEEE International Conference on Robotics and Automation ICRA LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 21-26, 2001 CL SEOUL, SOUTH KOREA SP IEEE Robot & Automat Soc, IEEE DE safe navigation; planetary; rovers; fuzzy logic; off-road mobility ID TRACTION CONTROL; VEHICLES; BRAKING; SYSTEM AB Operational safety and health monitoring are critical matters for autonomous field mobile robots such as planetary, rovers operating on challenging terrain. This paper describes relevant rover safety, and health issues and presents an approach to maintaining vehicle safety in a navigational context. The proposed rover safety module is composed of two distinct components: safe attitude (pitch and roll) management and safe traction management. Fuzzy logic approaches to reasoning about safe attitude and traction management are presented, wherein sensing of safety status and perception of terrain quality are used to infer safe speeds of traversal. Results of field tests and laboratory experiments are also described. The approach provides at? intrinsic safety cognizance and a capacity for reactive mitigation of navigation risks. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM tunstel@robotics.jpl.nasa.gov; howard@robotics.jpl.nasa.gov; seraji@robotics.jpl.nasa.gov NR 21 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-6576-3 J9 IEEE INT CONF ROBOT PY 2001 BP 1413 EP 1420 PG 8 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA BT31J UT WOS:000172615800226 ER PT S AU Shillcutt, K Whittaker, W AF Shillcutt, K Whittaker, W GP IEEE IEEE IEEE TI Solar navigational planning for robotic explorers SO 2001 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS I-IV, PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 21-26, 2001 CL SEOUL, SOUTH KOREA SP IEEE Robot & Automat Soc, IEEE AB This research considers the sin? motion and terrain in navigational planning. Robotic exploration of remote areas depends heavily on efficient use of power resources. An orbital ephemeris and terrain data are incorporated into a robotic planner to predict shadowing and solar power generation. The simulation and evaluation of coverage patterns are described, as well as searches,for continually sunlit paths or for nearby locations suitable fit, recharging or communicating with Earth. Aspects of the research were implemented as part of the Robotic Antarctic Meteorite Search project, for which simulations and field test results are given. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Shillcutt, K (reprint author), NASA, Lyndon B Johnson Space Ctr, 2101 NASA Rd 1 Code ER2, Houston, TX 77058 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-6576-3 J9 IEEE INT CONF ROBOT PY 2001 BP 1421 EP 1426 PG 6 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA BT31J UT WOS:000172615800227 ER PT S AU Howard, A Seraji, H Tunstel, E AF Howard, A Seraji, H Tunstel, E GP IEEE IEEE IEEE TI A rule-based fuzzy traversability index for mobile robot navigation SO 2001 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS I-IV, PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 21-26, 2001 CL SEOUL, SOUTH KOREA SP IEEE Robot & Automat Soc, IEEE DE terrain analysis; fuzzy logic; navigation AB This paper presents a rule-based Fuzzy Traversability, Index that quantifies the ease-of-traversal of a terrain by a mobile robot based on real-time measurements of terrain characteristics retrieved from imagery data. These characteristics include, but are not limited to: slope, roughness, hardness, and discontinuity. The proposed representation of terrain traversability incorporates an intuitive, linguistic approach for expressing terrain characteristics that is robust with respect to imprecision and uncertainty, in the terrain measurements. The terrain assessment method is tested and validated with a set of real-world imagery data. These tests demonstrate the capability of the terrain classification algorithm for perceiving hazards associated with terrain traversal. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Howard, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 11 Z9 11 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-6576-3 J9 IEEE INT CONF ROBOT PY 2001 BP 3067 EP 3071 PG 5 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA BT31J UT WOS:000172615800487 ER PT S AU Seraji, HO Howard, A Tunstel, E AF Seraji, HO Howard, A Tunstel, E GP IEEE IEEE IEEE TI Safe navigation on hazardous terrain SO 2001 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS I-IV, PROCEEDINGS SE IEEE International Conference on Robotics and Automation ICRA LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 21-26, 2001 CL SEOUL, SOUTH KOREA SP IEEE Robot & Automat Soc, IEEE ID TRAVERSABILITY AB This paper presents a new strategy for autonomous navigation of field mobile robots on hazardous natural terrain using a fuzzy logic approach and a novel measure of terrain tra vers ability, The navigation strategy is comprised of three simple, independent behaviors: seek-goal, traverse-terrain, and avoid-obstacle. The recommendations from these three behaviors are combined through appropriate weighting factors to generate the final steering and speed commands that are executed by the phi bot. The weighting factors are produced by fuzzy lo gicrules that take into account the current status of the phi bot. This navigation strategy requires no a priori information about the environment, and uses the on-board traversability analysis to enable the robot to select relatively easy-to-tr averse paths autonomously. Field test results obtained from implementation of the proposed algorithms on the commercial Pioneer A Trover are presented. These results demonstrate the real-time cap abilities of the terrain assessment and fuzzy logic navigation algorithms. C1 CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, NASA, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 2 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-6576-3 J9 IEEE INT CONF ROBOT PY 2001 BP 3084 EP 3091 PG 8 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA BT31J UT WOS:000172615800490 ER PT S AU Castano, A Will, P AF Castano, A Will, P GP IEEE IEEE IEEE TI Representing and discovering the configuration of Conro robots SO 2001 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS I-IV, PROCEEDINGS SE IEEE International Conference on Robotics and Automation ICRA LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 21-26, 2001 CL SEOUL, SOUTH KOREA SP IEEE Robot & Automat Soc, IEEE ID SYSTEM AB A Conro reconfigurable robot is formed by joining a set of self-contained modules in a particular configuration; the actions of the robot are the result of the coordinated actions of its modules. These actions can be controlled using a master-slave approach only if the master can map the particular configuration of the robot to one that it already knows how to control. In this paper we discuss how to describe this configuration using graphs, how to discover a robot configuration and how to identify it as a particular known configuration. The methodology used is very general and can be applied easily to other modular robots. Experimental results for Conro quadrupeds and snakes are presented. C1 Univ So Calif, Inst Informat Sci, Marina Del Rey, CA 90292 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Andres.Castano@jpl.nasa.gov NR 13 TC 24 Z9 36 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-6576-3 J9 IEEE INT CONF ROBOT PY 2001 BP 3503 EP 3509 PG 7 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA BT31J UT WOS:000172615800557 ER PT S AU Simons, RN Chun, DH Katehi, LPB AF Simons, RN Chun, DH Katehi, LPB BE Sigmon, B TI Micro electromechanical systems (MEMS) actuators for antenna reconfigurability SO 2001 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT IEEE MTT-S International Microwave Symposium CY MAY 20-25, 2001 CL PHOENIX, AZ SP IEEE, MTTS AB A novel microelectromechanical systems (MEMS) actuator for patch antenna reconfiguration is presented for the first time. A key feature is the capability of multi-band operation without greatly increasing the antenna element dimensions. Experimental results demonstrate that the center frequency can be reconfigured from few hundred MHz to few GHz away from the nominal operating frequency. C1 NASA, Glenn Res Ctr, Dynacs Engn Co Inc, Cleveland, OH 44135 USA. RP Simons, RN (reprint author), NASA, Glenn Res Ctr, Dynacs Engn Co Inc, Cleveland, OH 44135 USA. NR 4 TC 6 Z9 6 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0149-645X BN 0-7803-6713-8 J9 IEEE MTT-S PY 2001 BP 215 EP 218 PG 4 WC Engineering, Electrical & Electronic; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BU13J UT WOS:000175125500050 ER PT S AU Subramanyam, G Mohsina, N Al Zaman, A Miranda, F Van Keuls, F Romanofsky, R Warner, J AF Subramanyam, G Mohsina, N Al Zaman, A Miranda, F Van Keuls, F Romanofsky, R Warner, J BE Sigmon, B TI Ferroelectric thin-film based electrically tunable Ku-band coplanar waveguide components SO 2001 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT IEEE MTT-S International Microwave Symposium CY MAY 20-25, 2001 CL PHOENIX, AZ SP IEEE, MTTS ID DESIGN AB Barium strontium titanate (Ba0.6Sr0.4TiO3) thin-film based tunable coplanar waveguide (CPW) components were studied in this research. The CPW components modeled and experimentally verified include CPW transmission lines, resonators and 2-pole filters. The resonators and filters fabricated and tested exhibited a frequency tunability of approximately 3% for a bipolar bias voltage of +/-100V, corresponding to a peak biasing field of 40 kV/cm. C1 Univ Dayton, Dept ECE, Dayton, OH 45469 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Subramanyam, G (reprint author), Univ Dayton, Dept ECE, 300 Coll Pk, Dayton, OH 45469 USA. NR 4 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0149-645X BN 0-7803-6713-8 J9 IEEE MTT-S PY 2001 BP 471 EP 474 PG 4 WC Engineering, Electrical & Electronic; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BU13J UT WOS:000175125500109 ER PT S AU Maiwald, F Martin, S Bruston, J Maestrini, A Crawford, T Siegel, PH AF Maiwald, F Martin, S Bruston, J Maestrini, A Crawford, T Siegel, PH BE Sigmon, B TI 2.7 THz waveguide tripler using monolithic membrane diodes SO 2001 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT IEEE MTT-S International Microwave Symposium CY MAY 20-25, 2001 CL PHOENIX, AZ SP IEEE, MTTS ID 2.5-THZ AB The description and performance of an 850 to 2550 GHz waveguide tripler is presented The tripler utilizes GaAs monolithic membrane diodes (MOMED) in single and antiparallel pairs. Output power of approximate to 0.1muW is reported. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Maiwald, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 6 Z9 7 U1 2 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0149-645X BN 0-7803-6713-8 J9 IEEE MTT-S PY 2001 BP 1637 EP 1640 PG 4 WC Engineering, Electrical & Electronic; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BU13J UT WOS:000175125500383 ER PT S AU Martin, S Nakamura, B Fung, A Smith, P Bruston, J Maestrini, A Maiwald, F Siegel, P Schlecht, E Mehdi, I AF Martin, S Nakamura, B Fung, A Smith, P Bruston, J Maestrini, A Maiwald, F Siegel, P Schlecht, E Mehdi, I BE Sigmon, B TI Fabrication of 200 to 2700 GHz multiplier devices using GaAs and metal membranes SO 2001 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT IEEE MTT-S International Microwave Symposium CY MAY 20-25, 2001 CL PHOENIX, AZ SP IEEE, MTTS ID 2.5-THZ AB Multiplier device fabrication techniques have been developed to enable robust implementation of monolithic circuits well into the THz frequency range. To minimize the dielectric loading of the wave guides, some circuits are realized entirely on a 3mum thick GaAs membrane with metal beamleads acting as RF probes and DC contact points. Other designs retain some thicker GaAs as a support and handling structure, allowing a membrane of bare metal or thin GaAs to be suspended across an input or output wave guide. Extensive use is made of selective etches, both reactive ion (RIE) and wet chemical, to maintain critical dimensions. Electron beam (e-beam) lithography provides the small contact areas required at the highest frequencies. Planar multiplier circuits for 200 GHz to 2700 GHz have been demonstrated using a variety of metal and GaAs membrane configurations made available by these fabrication techniques. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Martin, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 23 Z9 23 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0149-645X BN 0-7803-6713-8 J9 IEEE MTT-S PY 2001 BP 1641 EP 1644 PG 4 WC Engineering, Electrical & Electronic; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BU13J UT WOS:000175125500384 ER PT S AU Schlecht, E Chattopadhyay, G Maestrini, A Fung, A Martin, S Pukala, D Bruston, J Mehdi, I AF Schlecht, E Chattopadhyay, G Maestrini, A Fung, A Martin, S Pukala, D Bruston, J Mehdi, I BE Sigmon, B TI 200, 400 and 800 GHz Schottky diode "substrateless" multipliers: Design and results SO 2001 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT IEEE MTT-S International Microwave Symposium CY MAY 20-25, 2001 CL PHOENIX, AZ SP IEEE, MTTS ID OSCILLATOR AB Several sub-millimeter doubler circuits have been designed and built using a new fabrication technology. To reduce the RF losses in the passive circuitry, the substrate under the transmission lines is etched away, leaving the metal suspended in air held by its edges on a GaAs frame. This allows the circuit to be handled and mounted easily, and makes it very robust. To demonstrate this technology, broadband balanced planar doublers have been built and tested at 400 GHz. The next generation 200, 400 and 800 GHz doublers with improved performance will also be discussed. The 368-424 GHz circuits were measured and achieved 20% efficiency at 387 GHz. The 3-dB bandwidth of the fix-tuned doubler is around 9%. The maximum output power measured is around 8 mW and drops down to 1mW at 417 GHz. This represents the highest frequency waveguide based planar doubler to date in the literature. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Schlecht, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 23 Z9 23 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0149-645X BN 0-7803-6713-8 J9 IEEE MTT-S PY 2001 BP 1649 EP 1652 PG 4 WC Engineering, Electrical & Electronic; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BU13J UT WOS:000175125500386 ER PT S AU Maestrini, A Bruston, J Pukala, D Martin, S Mehdi, H AF Maestrini, A Bruston, J Pukala, D Martin, S Mehdi, H BE Sigmon, B TI Performance of a 1.2 THz frequency tripler using a GaAs frameless membrane monolithic circuit SO 2001 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT IEEE MTT-S International Microwave Symposium CY MAY 20-25, 2001 CL PHOENIX, AZ SP IEEE, MTTS AB The first ever planar Schottky diode multiplier working over a THz will be presented in this paper. A tunerless 1.2 THz waveguide frequency tripler has been designed, fabricated and tested. The frequency multiplier consists of a 3 micron-thick GaAs frameless-membrane monolithic circuit, mounted in a split waveguide-block, which includes a built-in Picket-Potter horn. The 1.2 THz membrane tripler is driven by a 400 GHz solid-state chain composed of HEMT based power amplifiers followed by two tunerless planar diode frequency doublers. At room temperature, output power up to 80 microwatts was measured at 1126 GHz with a peak-efficiency of 0.9% and a 3dB bandwidth of about 3.5%. The output power of the multiplier chain increased dramatically with a decrease of the ambient temperature - up to 195 microwatts was measured at 120K. When further cooled to 50K the chain delivers power levels as high as 250 microwatts. To the best of our knowledge, this is the first demonstration of a fully planar multiplier chain at these frequencies, along with performance that supercedes current state-of-the-art performance of whisker-contacted sources. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Maestrini, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 168-314, Pasadena, CA 91109 USA. NR 11 TC 5 Z9 5 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0149-645X BN 0-7803-6713-8 J9 IEEE MTT-S PY 2001 BP 1657 EP 1660 PG 4 WC Engineering, Electrical & Electronic; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BU13J UT WOS:000175125500388 ER PT S AU Ponchak, GE Tentzeris, EM Papapolymerou, J AF Ponchak, GE Tentzeris, EM Papapolymerou, J BE Sigmon, B TI Coupling between microstrip lines embedded in polyimide layers for 3D-MMICs on Si SO 2001 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT IEEE MTT-S International Microwave Symposium CY MAY 20-25, 2001 CL PHOENIX, AZ SP IEEE, MTTS AB Three-dimensional circuits built upon multiple layers of polyimide are required for constructing Si/SiGe monolithic microwave/millimeter-wave integrated circuits on CMOS (low resistivity) Si wafers. However, the closely spaced transmission lines are susceptible to high levels of coupling, which degrades circuit performance. In this paper, Finite Difference Time Domain (FDTD) analysis and measured characteristics of novel shielding structures that significantly reduce coupling between embedded microstrip lines are presented. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Ponchak, GE (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 8 TC 4 Z9 4 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0149-645X BN 0-7803-6713-8 J9 IEEE MTT-S PY 2001 BP 1723 EP 1726 PG 4 WC Engineering, Electrical & Electronic; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BU13J UT WOS:000175125500403 ER PT S AU Samoska, L Leong, YC AF Samoska, L Leong, YC BE Sigmon, B TI 65-145 GHz InP MMIC HEMT medium power amplifiers SO 2001 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT IEEE MTT-S International Microwave Symposium CY MAY 20-25, 2001 CL PHOENIX, AZ SP IEEE, MTTS ID INPHEMT AB In this paper, we present two MMIC power amplifier designs utilizing InP HEMT technology. The first amplifier covers two full waveguide bands, WR10 (75-110 GHz) and WR8 (90-140 GRz), yielding a maximum output power of at least 25 mW between 65-140 GHz. The second design is optimized for the WR10 waveguide band and provides at least 13 dB of large signal gain over 75-110 GHz, and an output power of 40-50 mW. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Samoska, L (reprint author), CALTECH, Jet Prop Lab, M-S 168-314,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 9 Z9 10 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0149-645X BN 0-7803-6713-8 J9 IEEE MTT-S PY 2001 BP 1805 EP 1808 PG 4 WC Engineering, Electrical & Electronic; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BU13J UT WOS:000175125500422 ER PT B AU McClure, SS Gorelick, JL Pease, RL Rax, BG Ladbury, RL AF McClure, SS Gorelick, JL Pease, RL Rax, BG Ladbury, RL GP IEEE IEEE TI Total dose performance of radiation hardened voltage regulators and references SO 2001 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 10th IEEE Radiation Effects Data Workshop (REDW) held in conjunction with the 38th Annual IEEE Nuclear and Space Radiation Effects Conference CY JUL 16-20, 2001 CL VANCOUVER, CANADA SP IEEE Nucl & Plasma Sci Soc, IEEE AB Total dose tests of commercially available radiation hardened bipolar voltage regulators and references show reduced sensitivity to low dose rate enhancement and varying sensitivity to bias under exposure. Behavior of critical parameters in different dose rate and bias conditions is compared and the impact to hardness assurance methodology is discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP McClure, SS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7199-2 PY 2001 BP 1 EP 5 DI 10.1109/REDW.2001.960440 PG 5 WC Engineering, Electrical & Electronic; Physics, Nuclear SC Engineering; Physics GA BT43B UT WOS:000172972300001 ER PT B AU Nguyen, DN Scheick, LZ AF Nguyen, DN Scheick, LZ GP IEEE IEEE TI TID testing of ferroelectric nonvolatile RAM SO 2001 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 10th IEEE Radiation Effects Data Workshop (REDW) held in conjunction with the 38th Annual IEEE Nuclear and Space Radiation Effects Conference CY JUL 16-20, 2001 CL VANCOUVER, CANADA SP IEEE Nucl & Plasma Sci Soc, IEEE AB The test results of measurements performed on two different sizes of ferroelectric RAM (FeRAM) suggest the degradation is due to the low radiation tolerance of sense amplifiers and reference voltage generators which are based on commercial CMOS technology. This paper presents TID testing of 64Kb Ramtron FM1608 and 256Kb Ramtron FM1808. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nguyen, DN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7199-2 PY 2001 BP 57 EP 61 DI 10.1109/REDW.2001.960449 PG 5 WC Engineering, Electrical & Electronic; Physics, Nuclear SC Engineering; Physics GA BT43B UT WOS:000172972300010 ER PT B AU Scheick, LZ AF Scheick, LZ GP IEEE IEEE TI SEE evaluation of Digital Analog Converters for space applications SO 2001 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 10th IEEE Radiation Effects Data Workshop (REDW) held in conjunction with the 38th Annual IEEE Nuclear and Space Radiation Effects Conference CY JUL 16-20, 2001 CL VANCOUVER, CANADA SP IEEE Nucl & Plasma Sci Soc, IEEE AB SEE cross-sections were obtained for four different Digital to Analog Converters (DACs). The different types of DAC tested were: the Analog Devices DAC8420, the Analog Devices AD768, the Maxim MAX539, and the Xicor X9C503. Both of the Analog Devices DACs and the Maxim part were seen to be immune to latch-up, not latching even at 120 MeVcm(2)/mg. The Xicor part did latch-up with a threshold of 25 Me V-cm(2)/mg. Both Analog Devices DACs had clocked inputs which when constantly clocked rendered the device immune to SEU on the output line. The Xicor DAC had no clock option or function. All four devices had thresholds around 5 MeV-cm(2)/mg for output SEU. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Scheick, LZ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 3 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7199-2 PY 2001 BP 62 EP 66 DI 10.1109/REDW.2001.960451 PG 5 WC Engineering, Electrical & Electronic; Physics, Nuclear SC Engineering; Physics GA BT43B UT WOS:000172972300011 ER PT B AU Coss, JR AF Coss, JR GP IEEE IEEE TI Device susceptibility update: 1999-2000 SO 2001 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 10th IEEE Radiation Effects Data Workshop (REDW) held in conjunction with the 38th Annual IEEE Nuclear and Space Radiation Effects Conference CY JUL 16-20, 2001 CL VANCOUVER, CANADA SP IEEE Nucl & Plasma Sci Soc, IEEE AB This ninth biennial Compendium continues the previous work of Nichols, et al, on single event effects (SEE) on microcircuits first published in 1985. Because of the volume of SEE data that has generated over past years, this Compendium only presents data collected and/or published in the last two years. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 22 TC 4 Z9 4 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7199-2 PY 2001 BP 106 EP 126 DI 10.1109/REDW.2001.960458 PG 21 WC Engineering, Electrical & Electronic; Physics, Nuclear SC Engineering; Physics GA BT43B UT WOS:000172972300017 ER PT B AU Marshall, CJ Marshall, PW Carts, MA Reed, R Baier, S LaBel, K AF Marshall, CJ Marshall, PW Carts, MA Reed, R Baier, S LaBel, K GP IEEE IEEE TI Characterization of transient error cross sections in high speed commercial fiber optic data links SO 2001 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 10th IEEE Radiation Effects Data Workshop (REDW) held in conjunction with the 38th Annual IEEE Nuclear and Space Radiation Effects Conference CY JUL 16-20, 2001 CL VANCOUVER, CANADA SP IEEE Nucl & Plasma Sci Soc, IEEE ID SATELLITE DATA MANAGEMENT; PERFORMANCE AB This paper presents data on the single event transient (SET) response of several high speed commercial fiber optic links (FOLs). We show that commercial-grade technologies may be robust to SET in the natural space environment encountered in many satellite missions even for data rates in the 1 Gbps regime. In addition to characterizing the error cross section as a function of optical power and data rate, the angular dependence of the SET behavior is also quantified as a function of optical power. Note that receiver angular response has,some similarity to behavior observed in optocoupler technology and must be quantified for accurate predictions of on-orbit link error rates [1,2]. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Marshall, CJ (reprint author), NASA, Goddard Space Flight Ctr, Code 562 1, Greenbelt, MD 20771 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7199-2 PY 2001 BP 142 EP 145 DI 10.1109/REDW.2001.960461 PG 4 WC Engineering, Electrical & Electronic; Physics, Nuclear SC Engineering; Physics GA BT43B UT WOS:000172972300020 ER PT B AU Sun, XL Dautet, H AF Sun, XL Dautet, H GP IEEE IEEE TI Proton radiation damage of Si APD single photon counters SO 2001 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 10th IEEE Radiation Effects Data Workshop (REDW) held in conjunction with the 38th Annual IEEE Nuclear and Space Radiation Effects Conference CY JUL 16-20, 2001 CL VANCOUVER, CANADA SP IEEE Nucl & Plasma Sci Soc, IEEE ID SILICON AVALANCHE PHOTODIODES; NEUTRON; DETECTORS AB Proton radiation damage of Si avalanche photodiodes were measured at 53 to 189MeV proton energy. The annealing rates were monitored at -10 degreesC, room temperature, and 55 degreesC. The results are compared with the previously published data. C1 NASA, Goddard Space Flight Ctr, Laser Remote Sensing Branch, Greenbelt, MD 20771 USA. RP Sun, XL (reprint author), NASA, Goddard Space Flight Ctr, Laser Remote Sensing Branch, Code 924, Greenbelt, MD 20771 USA. RI Sun, Xiaoli/B-5120-2013 NR 20 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7199-2 PY 2001 BP 146 EP 150 DI 10.1109/REDW.2001.960462 PG 5 WC Engineering, Electrical & Electronic; Physics, Nuclear SC Engineering; Physics GA BT43B UT WOS:000172972300021 ER PT B AU Reed, RA Marshall, PW Ainspan, H Marshall, CJ Kim, HS Cressler, JD Niu, GF LaBel, KA AF Reed, RA Marshall, PW Ainspan, H Marshall, CJ Kim, HS Cressler, JD Niu, GF LaBel, KA GP IEEE IEEE TI Single Event Upset test results on a prescalar fabricated in IBM's 5HP Silicon Germanium Heterojunction Bipolar Transistors BiCMOS technology SO 2001 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 10th IEEE Radiation Effects Data Workshop (REDW) held in conjunction with the 38th Annual IEEE Nuclear and Space Radiation Effects Conference CY JUL 16-20, 2001 CL VANCOUVER, CANADA SP IEEE Nucl & Plasma Sci Soc, IEEE AB This paper presents heavy ion and proton Single Event Upset (SEU) test results on a IBM designed high-speed prescaler fabricated in Silicon Germanium (SiGe) Heterojunction Bipolar Transistor (HBT) BiCMOS process. These are the first published SEU results on this technology. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Reed, RA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7199-2 PY 2001 BP 172 EP 176 DI 10.1109/REDW.2001.960469 PG 5 WC Engineering, Electrical & Electronic; Physics, Nuclear SC Engineering; Physics GA BT43B UT WOS:000172972300026 ER PT S AU Sherrit, S Bao, X Sigel, DA Gradziel, MJ Askins, SA Dolgin, BP Bar-Cohen, Y AF Sherrit, S Bao, X Sigel, DA Gradziel, MJ Askins, SA Dolgin, BP Bar-Cohen, Y BE Yuhas, DE Schneider, SC TI Characterization of transducers and resonators under high drive levels SO 2001 IEEE ULTRASONICS SYMPOSIUM PROCEEDINGS, VOLS 1 AND 2 SE ULTRASONICS SYMPOSIUM LA English DT Proceedings Paper CT IEEE International Ultrasonic Symposium CY OCT 07-10, 2001 CL ATLANTA, GA SP Ultrason, Ferrelect, & Frequency Control Soc AB In many applications, piezoelectric transducers are driven at AC voltage levels well beyond the level for which the material was nominally characterized. In this paper we describe an experimental setup that allows for the determination of the main transducer or resonator properties under large AC drive. A sinusoidal voltage from a waveform generator is amplified and applied across the transducer/resonator in series with a known high power resistor. The amplitude of applied voltage and the amplitude and the relative phase of the current through the resistor are monitored on a digital scope. The frequency of the applied signal is swept through resonance and the voltage/current signals are recorded. After corrections for the series resistance and parasitic elements the technique allows for the determination of the complex impedance spectra of the sample as a function of frequency. In addition, access to the current signal allows for the direct investigation of non-linear effects through the application of Fourier transform techniques on the current signal. Our results indicate that care is required when interpreting impedance data at high drive level due to the frequency dependence of the dissipated power. Although the transducer/resonator at a single frequency and after many cycles may reach thermal equilibrium, the spectra as a whole cannot be considered an isothermal measurement due to the temperature change with frequency. Methods to correct for this effect will be discussed. Results determined from resonators of both soft and hard PZT and a ultrasonic horn transducer are presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sherrit, S (reprint author), CALTECH, Jet Prop Lab, Mail Stop 82-105,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 1 Z9 1 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1051-0117 BN 0-7803-7177-1 J9 ULTRASON PY 2001 BP 1097 EP 1100 PG 4 WC Acoustics; Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Acoustics; Engineering; Physics GA BU75C UT WOS:000176890800235 ER PT S AU Fettig, R AF Fettig, R GP SPIE SPIE TI MEMS in Space Science. SO 2001 INTERNATIONAL SYMPOSIUM ON MICROELECTRONICS, PROCEEDINGS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT International Symposium on Microelectronics CY OCT 09-11, 2001 CL BALTIMORE, MD SP Int Microelectr & Packaging Soc, SPIE DE MEMS; micro-machining; bolometer; micromirror; microshutter; micro-spectrometer; nanosatellite AB The application of MEMS devices for missions in space science faces challenges that are unique in many respects. The number of devices that are needed is small and the environmental constrains are significant. Subsequently the applications implemented are only those with high scientific return where only new micro devices are able to fulfill the requirements. Among the first were micro-machined detectors that perform better than conventionally produced devices. Next are micro optical arrays with levels of complexity that cannot be achieved in any other technology. Then there will be whole spectrometers that can go on missions for which anything else but a MEMS device is too heavy. In the future MEMS combined with improved electronics will enable Nanosatellites that can perform new task. C1 NASA, Goddard Space Flight Ctr, Raytheon ITSS, Greenbelt, MD 20771 USA. RP Fettig, R (reprint author), NASA, Goddard Space Flight Ctr, Raytheon ITSS, Code 693, Greenbelt, MD 20771 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4317-4 J9 P SOC PHOTO-OPT INS PY 2001 VL 4587 BP 14 EP 19 PG 6 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BT85F UT WOS:000174225600003 ER PT S AU Moran, ME AF Moran, ME GP SPIE SPIE TI Micro-scale avionics thermal management SO 2001 INTERNATIONAL SYMPOSIUM ON MICROELECTRONICS, PROCEEDINGS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT International Symposium on Microelectronics CY OCT 09-11, 2001 CL BALTIMORE, MD SP Int Microelectr & Packaging Soc, SPIE DE microelectronics; MEMS; microsystems; refrigerator; cooler; Stirling cycle AB Trends in the thermal management of avionics and commercial ground-based microelectronics are converging, and facing the same dilemma: a shortfall in technology to meet near-term maximum junction temperature and package power projections. Micro-scale devices hold the key to significant advances in thermal management, particularly micro-refrigerators/coolers that can drive cooling temperatures below ambient. A microelectromechanical system (MEMS) Stirling cooler is currently under development at the NASA Glenn Research Center to meet this challenge with predicted efficiencies that are an order of magnitude better than current and future thermoelectric coolers. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Moran, ME (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4317-4 J9 P SOC PHOTO-OPT INS PY 2001 VL 4587 BP 20 EP 25 PG 2 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BT85F UT WOS:000174225600004 ER PT S AU Sims, WH AF Sims, WH GP SPIE SPIE TI High efficiency microwave power amplifier: From the lab to industry SO 2001 INTERNATIONAL SYMPOSIUM ON MICROELECTRONICS, PROCEEDINGS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT International Symposium on Microelectronics CY OCT 09-11, 2001 CL BALTIMORE, MD SP Int Microelectr & Packaging Soc, SPIE AB Since the beginnings of space travel, various microwave power amplifier designs have been employed. These included Class-A, -B, and -C bias arrangements. However, shared limitation of these topologies is the inherent high total consumption of input power associated with the generation of RF/microwave power. The power amplifier has always been the largest drain for the limited available power on the spacecraft. Typically, the conversion efficiency of a microwave power amplifier is 10 to 20 percent. For a typical microwave power amplifier of 20 watts, input DC power of at least 100 watts is required. Such a large demand for input power suggests that a better method of RF/Microwave power generation is required The price paid for using a linear amplifier where high linearity is unnecessary includes: Higher initial and operating costs, Lower DC-to-RF conversion efficiency, High power consumption, Higher power dissipation and the accompanying need for higher capacity heat removal means, and an amplifier that is more prone to parasitic oscillation. The first use of a higher efficiency mode of power generation was described by Baxandall in 1959. This higher efficiency mode, Class-D, is achieved through distinct switching techniques to reduce the power losses associated with switching, conduction, and gate drive losses of a given transistor. C1 NASA, George C Marshall Space Flight Ctr, MSFC, AL 35812 USA. RP Sims, WH (reprint author), NASA, George C Marshall Space Flight Ctr, Bldg 4487,ED 18, MSFC, AL 35812 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4317-4 J9 P SOC PHOTO-OPT INS PY 2001 VL 4587 BP 405 EP 409 PG 3 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BT85F UT WOS:000174225600069 ER PT S AU Sims, WH AF Sims, WH GP SPIE SPIE TI The HP85192B EEFet3 GaAsFET nonlinear model used in the high efficiency microwave power amplifier (HEMPA) SO 2001 INTERNATIONAL SYMPOSIUM ON MICROELECTRONICS, PROCEEDINGS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT International Symposium on Microelectronics CY OCT 09-11, 2001 CL BALTIMORE, MD SP Int Microelectr & Packaging Soc, SPIE AB Most nonlinear circuit analysis programs that exist today were designed primarily for transient analysis. By incorporating more accurate models in simulation programs, accurate predictions of GaAs FET behavior can be accomplished. However, should the designer need to simulate GaAs FETs that operate at high DC-to-RF conversion efficiencies, a more sophisticated model is needed. A relevant and appropriate method is called harmonic-balance, as described by Quere et al. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Sims, WH (reprint author), NASA, George C Marshall Space Flight Ctr, Bldg 4487 ED18, Huntsville, AL 35812 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4317-4 J9 P SOC PHOTO-OPT INS PY 2001 VL 4587 BP 622 EP 627 PG 4 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BT85F UT WOS:000174225600106 ER PT B AU Maleki, L Iltchenko, V Huang, S Savchenkov, A AF Maleki, L Iltchenko, V Huang, S Savchenkov, A GP IEEE IEEE IEEE TI Micro-optical resonators and applications in optoelectronic oscillator SO 2001 INTERNATIONAL TOPICAL MEETING ON MICROWAVE PHOTONICS, TECHNICAL DIGEST LA English DT Proceedings Paper CT International Topical Meeting on Microwave Photonics (MWP 01) CY JUL 07-09, 2002 CL LONG BEACH, CA SP IEEE, IEEE Lasers & Electro Opt Soc, Microwave Theory & Techn Soc, IEE, Def Adv Res Project Agcy, Jet Propuls Lab, Natl Sci Fdn, OptIC, Raytheon Co, TRW, USAF,Off Sci Res, USAF, Res Lab, VSK Photon AB Whispering gallery mode resonators are attractive elements for photonics applications, since they offer extremely high quality factors (as high as 1010) with a small size. We have applied microresonators in the realization of a high performance, and small size opto-electronic oscillator (OEO). Specifically, we have studied the use of microspherical resonators as the optical delay element in the optoelectronic feedback loop of the OEO, and a highly efficient lithium niobate modulator based on a micro-resonator. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7003-1 PY 2001 BP 37 EP 40 PG 4 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BU05P UT WOS:000174875700010 ER PT B AU Satorius, EH Ye, Z Archer, ED AF Satorius, EH Ye, Z Archer, ED GP IEEE IEEE TI Polarization combining scheme for radio direction finding with multipath SO 2001 MILCOM, VOLS 1 AND 2, PROCEEDINGS: COMMUNICATIONS FOR NETWORK-CENTRIC OPERATIONS: CREATING THE INFORMATION FORCE LA English DT Proceedings Paper CT IEEE Military Communications Conference (MILCOM 2001) CY OCT 28-31, 2001 CL MCLEAN, VA SP IEEE, ComSoc, AFCEA, EDS, MITRE AB For NASA's Mars Sample Return (MSR) program, there is a strong need to enhance the received signal strength for the radio direction finding (RDF) application. In this paper we consider the possibility of linearly combining the outputs from two orthogonal, polarized antennas to prevent polarization loss. The problem is complicated due to the dynamics of the beacon transmitter. In particular, assume that the transmitter is rotating and that it radiates a linearly polarized wave. Initial results are based on the assumption of perpendicular incidence. It is also extended for arbitrary incidence, in which case there will be a gain and phase difference between the orthogonally polarized antenna pair outputs. An innovative algorithm for the polarization combining is proposed and performance data in multipath environment are presented with simulation results. The SNR improvement using this algorithm translates into a more favorable channel condition for the overall RDF system design. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Satorius, EH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7225-5 PY 2001 BP 383 EP 387 PG 5 WC Computer Science, Information Systems; Computer Science, Software Engineering; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BV22G UT WOS:000178199600072 ER PT B AU Stewart, DH Ivancic, WD Bell, TL Kachmar, BA Shell, D Leung, K AF Stewart, DH Ivancic, WD Bell, TL Kachmar, BA Shell, D Leung, K GP IEEE IEEE TI Application of mobile router to military communications SO 2001 MILCOM, VOLS 1 AND 2, PROCEEDINGS: COMMUNICATIONS FOR NETWORK-CENTRIC OPERATIONS: CREATING THE INFORMATION FORCE LA English DT Proceedings Paper CT IEEE Military Communications Conference (MILCOM 2001) CY OCT 28-31, 2001 CL MCLEAN, VA SP IEEE, ComSoc, AFCEA, EDS, MITRE AB Cisco System and NASA Glenn Research Center under a NASA Space Act Agreement have been performing joint networking research to apply Internet technologies and protocols to space-based communications. During this time, Cisco Systems developed the mobile-router which NASA and Cisco jointly tested. The early field trials of this technology have been successfully completed. The mobile-router is software code that resides in a network router. A Mobile-Router allows entire networks to roam while maintaining connectivity to the Internet. This router code is pertinent to a myriad of applications for both the government and commercial sectors. This technology will be applied to the wireless battlefield. NASA and the DoD will utilize this technology for near-planetary observation and sensing spacecraft. It is the enabling technology for communication via the Internet or Intranets to aircraft. Information such as weather, air traffic control, voice and video can be easily and inexpensively transmitted to the aircraft using Internet protocols. The mobile router can be incorporated into emergency vehicles particularly ambulances and life-flight aircraft to provide real-time connectivity back to the hospital and healthcare experts. Commercial applications include entertainment services, IP telephone, and Internet connectivity for cruise ships, commercial shipping, tour busses, aircraft, and eventually cars. This paper will briefly describe the mobile router operation. An upcoming wide area network field test with application to US Coast Guard communications will be described. The paper will also highlight military and government networks that will benefit from the deployment of mobile router and the associated applications. C1 NASA, Glenn Res Ctr, Cleveland, OH USA. RP Stewart, DH (reprint author), NASA, Glenn Res Ctr, Cleveland, OH USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7225-5 PY 2001 BP 388 EP 396 PG 9 WC Computer Science, Information Systems; Computer Science, Software Engineering; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BV22G UT WOS:000178199600073 ER PT B AU Ishac, J Allman, M AF Ishac, J Allman, M GP IEEE IEEE TI On the performance of TCP spoofing in satellite networks SO 2001 MILCOM, VOLS 1 AND 2, PROCEEDINGS: COMMUNICATIONS FOR NETWORK-CENTRIC OPERATIONS: CREATING THE INFORMATION FORCE LA English DT Proceedings Paper CT IEEE Military Communications Conference (MILCOM 2001) CY OCT 28-31, 2001 CL MCLEAN, VA SP IEEE, ComSoc, AFCEA, EDS, MITRE AB In this paper, we analyze the performance of TCP in a network that consists of both satellite and terrestrial components. One method, proposed by outside research, to improve the performance of data transfers over satellites is to use a performance enhancing proxy often dubbed "spoofing". Spoofing involves the transparent splitting of a TCP connection between the source and destination by some entity within the network path. In order to analyze the impact of spoofing, we constructed a simulation suite based around the network simulator ns-2. The simulation reflects a host with a satellite connection to the Internet and allows the option to spoof connections just prior to the satellite. The methodology used in our simulation allows us to analyze spoofing over a large range of file sizes and under various congested conditions, while prior work on this topic has primarily focused on bulk transfers with no congestion. As a result of these simulations, we find that the performance of spoofing is dependent upon a number of conditions. C1 NASA, Glenn Res Ctr, Satellite Networks & Architectures Branch, Cleveland, OH USA. RP Ishac, J (reprint author), NASA, Glenn Res Ctr, Satellite Networks & Architectures Branch, Cleveland, OH USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7225-5 PY 2001 BP 700 EP 704 PG 5 WC Computer Science, Information Systems; Computer Science, Software Engineering; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BV22G UT WOS:000178199600128 ER PT B AU Ye, Z Satorius, EH Vilnrotter, VA Pham, TT Fort, DN AF Ye, Z Satorius, EH Vilnrotter, VA Pham, TT Fort, DN GP IEEE IEEE TI Large antenna array techniques for very low SNR channels SO 2001 MILCOM, VOLS 1 AND 2, PROCEEDINGS: COMMUNICATIONS FOR NETWORK-CENTRIC OPERATIONS: CREATING THE INFORMATION FORCE LA English DT Proceedings Paper CT IEEE Military Communications Conference (MILCOM 2001) CY OCT 28-31, 2001 CL MCLEAN, VA SP IEEE, ComSoc, AFCEA, EDS, MITRE ID CONSTANT MODULUS SIGNALS; MANIFOLD INTERPOLATION; ESPRIT AB In this paper, various arraying techniques are studied focusing on the very low received signal SNR channel conditions commonly found in deep space communications applications. These include correlation-based blind approaches as well as a sub-space based superresolution approach. In addition to weak received signals, atmospheric turbulence and spatially correlated interference from nearby planets (and possibly quasars) creates additional channel impairment. It is demonstrated that the sub-space based MUSIC algorithm is a strong candidate for this application that can provide great angle separation accuracy, and interference suppression capability. Adaptive beamforming techniques in combination with the MUSIC algorithm provide a flexible platform to combat channel impairment. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ye, Z (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7225-5 PY 2001 BP 1283 EP 1290 PG 8 WC Computer Science, Information Systems; Computer Science, Software Engineering; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BV22G UT WOS:000178199600238 ER PT B AU Ye, Z Satorius, EH Jedrey, TC Temple, K AF Ye, Z Satorius, EH Jedrey, TC Temple, K GP IEEE IEEE TI Enhancement of Avanced Range Telemetry (ARTM) channels via blind equalization SO 2001 MILCOM, VOLS 1 AND 2, PROCEEDINGS: COMMUNICATIONS FOR NETWORK-CENTRIC OPERATIONS: CREATING THE INFORMATION FORCE LA English DT Proceedings Paper CT IEEE Military Communications Conference (MILCOM 2001) CY OCT 28-31, 2001 CL MCLEAN, VA SP IEEE, ComSoc, AFCEA, EDS, MITRE AB The Joint Services Advanced Range Telemetry (ARTM) Program at Edwards Air Force Base has been evaluating FQPSK-B for possible upgrades to the existing telemetry equipment. It has been found in the wideband channel sounding experiments sponsored by ARTM that the in-flight fading channel can be modeled as a 3-ray multipath channel([1]). Delay spread for a typical in-flight channel is in the order of 300 nanoseconds. Furthermore, the pre-flight channel is characterized by much more severe multipath, in which the delay spread is in the order of microseconds covering one or more symbols when the FQPSK-B transceiver operates at a rate of millions of symbols per second. This adverse channel condition inevitably causes tremendous distortion in the received signals due to severe inter-symbol interference (ISI) from the multipath. This paper provides an assessment of the potential ability of blind equalization to reduce the FQPSK-B system susceptibility to degradation caused by dynamic frequency selective fading in the aeronautical telemetry environment. In particular, a blind equalizer applique that can be inserted prior to the demodulator without knowledge of the received signal such as carrier frequency, symbol timing and sequence, etc, is proposed. Since it is desired that the equalizer applique operate independently of the carrier frequency and given that the modulation of interest is constant envelope (PCM-FM or FQPSK-B), we have selected the constant modulus algorithm (CMA)([2]) Cost function for implementation. Extensive tests on both simulated and recorded FQPSK-B data transmitted over different ARTM channels have been conducted and the blind equalizer structure has shown substantial improvements, even on the difficult ARTM pre-flight channels. The CMA adapts the equalizer coefficients to minimize the deviation of the output envelope from an arbitrary constant level. This paper depicts the pre-flight and in-flight channel conditions using time and spectral domain measurement. It quantifies the benefit of the blind CMA tapped delay line equalizer. Due to the extensive signal processing requirements associated with the very high sampling rate (100 MHz) of the FQPSK-B system, hardware implementation complexity is very high. Complexity reduction issues regarding the implementation of the CMA using Field Programmable Gate Array (FPGA) will also be presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ye, Z (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7225-5 PY 2001 BP 1399 EP 1404 PG 6 WC Computer Science, Information Systems; Computer Science, Software Engineering; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BV22G UT WOS:000178199600261 ER PT B AU Chau, SN Smith, J Tai, AT AF Chau, SN Smith, J Tai, AT GP IEEE IEEE TI A design-diversity based fault-tolerant COTS avionics bus network SO 2001 PACIFIC RIM INTERNATIONAL SYMPOSIUM ON DEPENDABLE COMPUTING, PROCEEDINGS LA English DT Proceedings Paper CT 8th Pacific Rim International Symposium on Dependable Computing (PRDC 2001) CY DEC 17-19, 2001 CL SEOUL, SOUTH KOREA SP IEEE, Comp Soc Tech Comm Fault Tolerant Comp, Sungkyunkwan Univ, Korean Informat Processing Soc, Electr & Telecommun Res Inst, Korean Soc Internet Informat, IFIP WG10 4 AB This paper describes a COTS bus network architecture consisted of the IEEE 1394 and SpaceWire buses. This architecture is based on the multi-level fault tolerance design methodology proposed by Chau but has much less overhead than the original IEEE 1394/(IC)-C-2 implementation. The simplifications are brought about by the topological flexibility and high performance of the SpaceWire. The Space Wire can forma connected graph that embeds multiple spanning trees. This is a significant advantage because it allows the IEEE 1394 bus to select a different tree topology when a fault occurs. It also has sufficient performance to stand in for IEEE 1394 bus during fault recovery, so that a backup IEEE 1394 bus is no longer required. These two buses are very compatible at the physical level and therefore can easily be combined. Analysis of the effectiveness of the IEEE 1394/SpaceWire architecture shows that it can achieve the same fault tolerance capability as the IEEE 1394/(IC)-C-2 architecture with less redundancy. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Savio.Chau@jpl.nasa.gov; Joseph.F.Smith@jpl.nasa.gov; a.t.tai@ieee.org NR 15 TC 2 Z9 4 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1414-6 PY 2001 BP 35 EP 42 DI 10.1109/PRDC.2001.992677 PG 8 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BT76R UT WOS:000173975000005 ER PT B AU Simons, RN Goverdhanam, K Katehi, LPB AF Simons, RN Goverdhanam, K Katehi, LPB BE Ponchak, GE TI Novel low loss wide-band multi-port integrated circuit technology for RF/microwave applications SO 2001 TOPICAL MEETING ON SILICON MONOLITHIC INTEGRATED CIRCUITS IN RF SYSTEMS, DIGEST OF PAPERS LA English DT Proceedings Paper CT 3rd IEEE Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems CY 2001 CL UNIV MICHIGAN, ANN ARBOR, MI SP IEEE Microwave Theory & Techn Soc, NASA Glenn Res Ctr, USA Res Off HO UNIV MICHIGAN AB In this paper, novel low loss, wide-band coplanar stripline technology for RF/microwave integrated circuits Is demonstrated on high resistivity silicon wafer. In particular, the fabrication process for the deposition of spin-on-glass (SOG) as a dielectric layer, the etching of microvias for the vertical interconnects, the design methodology for the multiport circuits and their measured/simulated characteristics are graphically illustrated. The study shows that circuits with very low loss, large bandwidth and compact size are feasible using this technology. This multilayer planar technology has potential to significantly enhance RF/microwave IC performance when combined with semiconductor devices and microelectromechanical systems (MEMS). C1 NASA, Glenn Res Ctr, QSS Inc, Cleveland, OH 44135 USA. RP Simons, RN (reprint author), NASA, Glenn Res Ctr, QSS Inc, Cleveland, OH 44135 USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7129-1 PY 2001 BP 60 EP 63 DI 10.1109/SMIC.2001.942341 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BT48T UT WOS:000173130900011 ER PT B AU Leon, R AF Leon, R BE Ponchak, GE TI Self-assembled III-V quantum dots: Potential for silicon optoelectronics SO 2001 TOPICAL MEETING ON SILICON MONOLITHIC INTEGRATED CIRCUITS IN RF SYSTEMS, DIGEST OF PAPERS LA English DT Proceedings Paper CT 3rd IEEE Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems CY 2001 CL UNIV MICHIGAN, ANN ARBOR, MI SP IEEE Microwave Theory & Techn Soc, NASA Glenn Res Ctr, USA Res Off HO UNIV MICHIGAN DE nanotechnology; Stranski-Krastanow quantum dots; photoluminescence; III-V compounds ID VISIBLE LUMINESCENCE; THRESHOLD CURRENT; ORGANIZED GROWTH; INGAAS; LASERS; GAAS; RECOMBINATION; TEMPERATURE; TRANSITIONS; ISLANDS AB The basic optoelectronic properties of self-forming InGaAs/InAlAs QDs are examined in parallel with their device implementation. Recent results showing remarkably good tolerance to radiation induced point defects and good luminescence emission from InAs/InGaAs QDs grown on dislocation arrays are discussed in terms of an enabling technology which will allow optoelectronics integration with silicon technology. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Leon, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 33 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7129-1 PY 2001 BP 79 EP 87 DI 10.1109/SMIC.2001.942345 PG 9 WC Engineering, Electrical & Electronic SC Engineering GA BT48T UT WOS:000173130900015 ER PT B AU Filman, RE Lee, DD AF Filman, RE Lee, DD BE Takizawa, M TI Redirecting by injector SO 21ST INTERNATIONAL CONFERENCE ON DISTRIBUTED COMPUTING SYSTEMS WORKSHOPS, PROCEEDINGS LA English DT Proceedings Paper CT 21st IEEE International Conference on Distributed Computing Systems CY APR 16-19, 2001 CL Phoenix, AZ SP IEEE Comp Soc, Tech Comm Distributed Processing AB We describe the Object Infrastructure Framework, a system that seeks to simplify the creation of distributed applications by injecting behavior on the communication paths between components. We touch on some of the ilities and services that can be achieved with injector technology, and then focus on the uses of redirecting injectors, injectors that rake requests directed at a particular server and generate requests directed at others. We close by noting that OIF is an Aspect-Oriented Programming system, and comparing OIF to related work. C1 NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. RP Filman, RE (reprint author), NASA, Ames Res Ctr, RIACS, MS 269-2, Moffett Field, CA 94035 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1080-9 PY 2001 BP 141 EP 146 PG 4 WC Computer Science, Information Systems; Telecommunications SC Computer Science; Telecommunications GA BS21S UT WOS:000169104400020 ER PT S AU Opila, EJ Halbig, MC AF Opila, EJ Halbig, MC BE Singh, M Jessen, T TI Oxidation of ZrB(2)-SiC SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE Ceramic Engineering and Science Proceedings LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc AB In this paper the oxidation behavior of ZrB(2)-20 vol% SiC is examined. Samples were exposed in stagnant air in a zirconia furnace (Deltech, Inc.) at temperatures of 1327, 1627, and 1927degreesC for ten ten-minute cycles. Samples were removed from the furnace after one, five, and ten cycles. Oxidized material was characterized by mass change when possible, x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Oxidation kinetics, oxide scale development, and matrix recession were monitored as a function of time and temperature. Oxidation and recession rates of ZrB(2) - 20 vol% SiC were adequately modeled by parabolic kinetics. Oxidation rates of this material are rapid, allowing only very short-term application in air or other high oxygen partial pressure environments. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Opila, EJ (reprint author), NASA, Glenn Res Ctr, 21000 Brookport Rd, Cleveland, OH 44135 USA. NR 5 TC 46 Z9 48 U1 0 U2 2 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 3 BP 221 EP 228 PG 8 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85N UT WOS:000183407900027 ER PT S AU Salem, J Calomino, A Allen, R Powers, L AF Salem, J Calomino, A Allen, R Powers, L BE Singh, M Jessen, T TI Slow crack growth of sapphire SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc ID FATIGUE C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Salem, J (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 3 BP 289 EP 297 PG 9 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85N UT WOS:000183407900035 ER PT S AU Ogbuji, LUJT Wheeler, DR McCue, TR AF Ogbuji, LUJT Wheeler, DR McCue, TR BE Singh, M Jessen, T TI Process-induced carbon sub-layer in SiC/BN/SiC composites: Characterization and consequences SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc ID DEGRADATION; NICALON; FIBER AB Following our detection of films of elemental carbon in the Hi-Nicalon(TM)/BN/SiC composite and its deleterious effect on oxidative durability, we have examined other SiC/BN/SiC systems. The problem is pervasive, and significant residues of free carbon are confirmed in Sylramic(TM)/BN/SiC materials. Effective techniques for routine detection and characterization of adventitious carbon in SiC/BN/SiC composites are discussed. C1 QSS Grp Inc, NASA Glenn Res Ctr, Cleveland, OH 44135 USA. RP Ogbuji, LUJT (reprint author), QSS Grp Inc, NASA Glenn Res Ctr, Cleveland, OH 44135 USA. NR 10 TC 1 Z9 1 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 3 BP 379 EP 387 PG 9 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85N UT WOS:000183407900045 ER PT S AU Hurwitz, FI Chayka, PV Scott, JM AF Hurwitz, FI Chayka, PV Scott, JM BE Singh, M Jessen, T TI Progress on BN and doped-BN coatings on woven fabrics SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc ID HIGH-TEMPERATURE OXIDATION; CHEMICAL-VAPOR-DEPOSITION; BORON-NITRIDE; CERAMIC COMPOSITES; FILMS; INTERPHASE; BORAZINE; SIBN AB A novel, multistep process for applying interface coatings to woven structures using a pulsed CVD process is being evaluated. Borazine (B3N3H6), a neat liquid, and several Si precursors are used in the process to produce BN and SiBN coatings on Hi- Nicalon fabrics and preforms. A three variable, two level, full factorial matrix is proposed to define the influence of processing parameters. Coating morphology, uniformity and chemistry are characterized by field emission scanning electron microscopy (FESEM), energy dispersive (EDS) and Auger spectroscopies. C1 NASA Glenn Res Ctr, Cleveland, OH 44135 USA. RP Hurwitz, FI (reprint author), NASA Glenn Res Ctr, Cleveland, OH 44135 USA. NR 19 TC 2 Z9 2 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 3 BP 389 EP 397 PG 9 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85N UT WOS:000183407900046 ER PT S AU Fernandez, JM Sayir, A AF Fernandez, JM Sayir, A BE Singh, M Jessen, T TI Creep of directionally solidified Al2O3/Er3Al5O12 fibers with hypoeutectic composition SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc ID MECHANICAL-PROPERTIES AB The microstructure and high temperature deformation characteristic of directionally solidified Al2O3/Er3Al5O12 fibers with hypo-eutectic composition were studied between 1350 degreesC and 1600 degreesC at constant load. This eutectic system has a unique cellular microstructure with high aspect ratio (up to 100) Al2O3 cells and Er3Al5O12 or Al2O3/Er3Al5O12 eutectic boundaries. The Al2O3/Er3Al5O12 system has a very high creep resistance, comparable to c-axis sapphire. Dislocation plasticity is suggested as the most plausible deformation mechanism. The dislocation behavior in each phase and their relevance to the very high creep resistance of this polyphase system are discussed. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Fernandez, JM (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RI Martinez Fernandez, Julian/K-1826-2012 OI Martinez Fernandez, Julian/0000-0002-1199-6638 NR 18 TC 6 Z9 6 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 3 BP 421 EP 428 PG 8 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85N UT WOS:000183407900050 ER PT S AU Yun, HM Gyekenyesi, JZ Chen, YL Wheeler, DR DiCarlo, JA AF Yun, HM Gyekenyesi, JZ Chen, YL Wheeler, DR DiCarlo, JA BE Singh, M Jessen, T TI Tensile behavior of SiC/SiC composites reinforced by treated Sylramic sic fibers SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc AB Near stoichiometric SiC fibers, such as Sylramic and Hi-Nicalon Type S, display very good thermomechanical properties that are essential for high-temperature structural ceramic matrix composites (CMC). Recently NASA has developed a treatment for the Sylramic fiber that further improves its creep-rupture properties and environmental interactions by removing boron from the bulk and forming a thin in-situ BN coating on the fiber surface. To understand its benefits for fiber-controlled CMC properties, this treatment was performed on two-dimensional 0/90 degree woven Sylramic fabric prior to forming SiC/SiC composites with a BN interphase and a melt-infiltration SiC matrix. Tensile stress-strain behavior for the CMC showed a high modulus followed by graceful cracking at a high proportional limit, but more importantly a higher ultimate strength than for the SiC/SiC composites fabricated in the same manner, but reinforced by untreated Sylramic and Hi-Nicalon Type S fibers. It is believed that this improved ultimate strength behavior is primarily related to the in-situ BN coating that acts to protect the fibers from environmental effects introduced during the CMC fabrication process. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Yun, HM (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 12 TC 22 Z9 23 U1 2 U2 3 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 3 BP 521 EP 531 PG 11 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85N UT WOS:000183407900060 ER PT S AU Morscher, GN Hurst, J AF Morscher, GN Hurst, J BE Singh, M Jessen, T TI Stress-rupture and stress-relaxation of SiC/SiC composites at intermediate temperature SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc ID CARBON; AIR AB Tensile static stress and static strain experiments were performed on woven Sylramic(R) (Dow Coming, Midland, MI) and Hi-Nicalon(TM) (Nippon Carbon, Japan) fiber reinforced, BN interphase, melt-infiltrated SiC matrix composites at 815degreesC. Acoustic emission was used to monitor the damage accumulation during the test. The stress-rupture properties of Sylrami(R) composites were superior to that of Hi-Nicalon(TM) composites. Conversely, the applied strain levels that Hi-Nicalon(TM) composites can withstand for stress-relaxation experiments were superior to Sylramic(R) composites; however, at a cost of poor retained strength properties for Hi-Nicalon(TM) composites. Sylramic composites exhibited much less stress-oxidation induced matrix cracking compared to Hi-Nicalon(TM) composites. This was attributed to the greater stiffness and roughness of Sylramic(R) fibers themselves and the lack of a carbon layer between the fiber and the BN interphase for Sylramic(R) composites, which existed in Hi-Nicalon(TM) composites. Due to the lack of stress-relief for Sylramic composites, time to failure for Sylramic(R) composite stress-relaxation experiments was not much longer than for stress-rupture experiments when comparing the peak stress condition for stress-relaxation with the applied stress of stress-rupture. C1 NASA, Glenn Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Morscher, GN (reprint author), NASA, Glenn Res Ctr, Ohio Aerosp Inst, MS 106-5, Cleveland, OH 44135 USA. NR 9 TC 6 Z9 6 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 3 BP 539 EP 546 PG 8 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85N UT WOS:000183407900062 ER PT S AU Morscher, GN Gyekenyesi, A AF Morscher, GN Gyekenyesi, A BE Singh, M Jessen, T TI Room temperature creep of SiC/SiC composites SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc ID MODAL ACOUSTIC-EMISSION AB During a recent experimental study, time dependent deformation was observed for a damaged Hi-Nicalon(TM) reinforced, BN interphase, chemically vapor infiltrated SiC matrix composites subjected to static loading at room temperature. The static load curves resembled primary creep curves. In addition, acoustic emission was monitored during the test and significant AE activity was recorded while maintaining a constant load, which suggested matrix cracking or interfacial sliding. For similar composites with carbon interphases, little or no time dependent deformation was observed. Evidently, exposure of the BN interphase to the ambient environment resulted in a reduction in the interfacial mechanical properties, i.e. interfacial shear strength and/or debond energy. These results were in qualitative agreement with observations made by Eldridge of a reduction in interfacial shear stress with time at room temperature as measured by fiber push-in experiments. C1 NASA, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Morscher, GN (reprint author), NASA, Ohio Aerosp Inst, MS 106-5, Cleveland, OH 44135 USA. NR 10 TC 1 Z9 1 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 3 BP 547 EP 552 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85N UT WOS:000183407900063 ER PT S AU Hurwitz, FI Calomino, AM Abdul-Aziz, A McCue, TR AF Hurwitz, FI Calomino, AM Abdul-Aziz, A McCue, TR BE Singh, M Jessen, T TI C-coupon studies of CMCs: Fracture behavior and microstructural characterization SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc ID TRANSVERSE AB A curved beam "C-coupon" was used to assess fracture behavior in a Sylramic(TM)/melt infiltration (MI) SiC matrix composite. Failure stresses and fracture mechanisms, as determined by optical and scanning electron microstructual analysis, are compared with finite element stress calculations to analyze failure modes. Material microstructure was found to have a strong influence on mechanical behavior. Fracture occurs in interlaminar tension (ILT), provided that the ratio of ILT to tensile strength for the material is less than the ratio of radial to hoop stresses for the C-coupon geometry. Utilization of 3D architectures to improve interlaminar strength requires significant development efforts to incorporate through thickness fibers in regions with high curvatures while maintaining uniform thickness, radius and microstructure. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Hurwitz, FI (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 8 TC 0 Z9 0 U1 1 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 3 BP 577 EP 584 PG 8 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85N UT WOS:000183407900067 ER PT S AU Choi, SR Gyckenyesi, JP AF Choi, SR Gyckenyesi, JP BE Singh, M Jessen, T TI Effect of load rate on tensile strength of various CFCCs at elevated temperatures - An approach to life prediction testing SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc ID CERAMIC-MATRIX COMPOSITE; CRACK-GROWTH AB Strength of three continuous fiber-reinforced ceramic composites, including SiC/CAS-II, SiC/MAS-5 and SiC/SiC, was determined as a function of test rate in air at 1100 - 1200degreesC. All three composite materials exhibited a strong dependency of strength on test rate, similar to the behavior observed in many advanced monolithic ceramics at elevated temperatures. The application of the preloading technique as well as the prediction of life from one loading configuration (constant stress-rate) to another (constant stress loading) suggested that the overall macroscopic failure mechanism of the composites would be the one governed by a power-law type of damage evolution/accumulation, analogous to slow crack growth commonly observed in advanced monolithic ceramics. It was further found that constant stress-rate testing could be used as an alternative to life prediction test methodology even for the composite materials at least for the short range of lifetime. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Choi, SR (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 13 TC 3 Z9 3 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 3 BP 597 EP 606 PG 10 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85N UT WOS:000183407900069 ER PT S AU Halbig, MC AF Halbig, MC BE Singh, M Jessen, T TI Stressed oxidation and modeling of C/SiC in oxidizing environments SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc ID KINETICS; MATRIX AB Carbon fiber reinforced silicon carbide matrix composites (C/SiC) are a promising material for use in many high temperature structural applications. The proposed applications are primarily in aerospace, i.e., nozzles, thrusters, turbopumps, brakes, and heat shields. However, the susceptibility of carbon fiber to oxidation has hindered its application in long term and reusable applications. This is due to reductions in composite strength and life during exposure in oxidizing environments. In order to better understand environmental effects on C/SiC materials, stressed oxidation (creep rupture) tests were conducted in an air environment at sustained loads at elevated temperatures. A temperature within each of the two primary oxidation kinetics regimes (diffusion controlled and reaction controlled) was chosen. Microstructural analysis of tested samples, which show environmental degradation of carbon fibers, will be discussed. A finite difference model will be used to simulate the oxidation of carbon fiber in a silicon carbide matrix. The model is to be used for predicting composite life and/or strength reduction of C/SiC in elevated temperature oxidizing environments under sustained tensile load conditions. C1 NASA, Glenn Res Ctr, Vehicle Technol Directorate, Army Res Labs, Cleveland, OH 44135 USA. RP Halbig, MC (reprint author), NASA, Glenn Res Ctr, Vehicle Technol Directorate, Army Res Labs, 2100 Brookpk Rd,MS 106-1, Cleveland, OH 44135 USA. NR 8 TC 3 Z9 4 U1 0 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 3 BP 625 EP 632 PG 8 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85N UT WOS:000183407900072 ER PT S AU Eldridge, JI Lee, KN AF Eldridge, JI Lee, KN BE Singh, M Jessen, T TI Phase evolution of BSAS in environmental barrier coatings SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc ID CERAMICS AB Barium strontium aluminosilicate (BSAS) has been demonstrated to be a beneficial constituent in coatings that prevent high-temperature environmental degradation of SiC. Promising plasma-sprayed environmental barrier coatings (EBCs) have been produced using BSAS as a top layer above a mullite bottom layer that includes a significant BSAS second phase. Depending on deposition conditions and thermal treatments, BSAS can be present in the amorphous, hexagonal celsian, or monoclinic celsian phases. Because of differences in stability, volume, and coefficient of thermal expansion (CTE), the phase content is expected to significantly affect the EBC performance. While the monoclinic celsian phase is believed to be the most desirable due to its stability and low CTE, conversion of the hexagonal phase to the monoclinic can be very sluggish and difficult to achieve. In this study, Raman microscopy was applied to track the phase evolution of BSAS in these coatings with heat treatment. Striking differences were observed in the phase evolution occurring in the BSAS top layer compared to the evolution of the BSAS second phase in the mullite bottom layer. The implications of the observed BSAS phase evolution on stress development, and therefore coating lifetime, are discussed. A comparison is also made with EBCs incorporating strontium aluminosilicate (SAS) in place of BSAS, since the hexagonal phase is expected to convert more readily to monoclinic phase with SAS. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Eldridge, JI (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 11 TC 7 Z9 7 U1 1 U2 8 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 4 BP 383 EP 390 PG 8 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85P UT WOS:000183408400046 ER PT S AU Fox, DS Zhu, DM Miller, RA AF Fox, DS Zhu, DM Miller, RA BE Singh, M Jessen, T TI Simulated engine test of combustor mini-segments using a high power CO2 laser SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc ID THERMAL BARRIER COATINGS AB A laser test rig has been developed for durability studies of ceramic thermal barrier coatings for combustor applications. By using a high power laser optic system, the test rig is capable of achieving temperature gradients across the coating thickness, as well as tailored temperature distributions on the coated combustor mini-segment surface. Realistic engine combustor high-temperature, and moderately high-pressure, conditions are achieved with a 6-atm, high-pressure chamber system and by controlling appropriate backside cooling gas temperatures and flow rates. Thermal barrier coating sintering/creep, thermal conductivity, and stress/strain data have been obtained from laser heat flux simulated engine component tests. C1 NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Fox, DS (reprint author), NASA, John H Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 2 TC 0 Z9 0 U1 1 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 4 BP 409 EP 416 PG 8 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85P UT WOS:000183408400049 ER PT S AU Zhu, DM Lee, KN Miller, RA AF Zhu, DM Lee, KN Miller, RA BE Singh, M Jessen, T TI Thermal conductivity and thermal gradient cyclic behavior of refractory silicate coatings on SiC/SiC ceramic matrix composites SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc ID ENVIRONMENTAL BARRIER COATINGS; SI-BASED CERAMICS AB Plasma-sprayed mullite and BSAS coatings have been developed to protect SiC/SiC ceramic matrix composites from high temperature environmental attack. In this study, thermal conductivity and thermal barrier functions of these coating systems are evaluated using a laser high-heat-flux test rig. The effects of water vapor on coating thermal conductivity and durability are studied by using alternating furnace and laser thermal gradient cyclic tests. The influence of laser high-thermal-gradient cycling on coating failure modes is also investigated. C1 NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Zhu, DM (reprint author), NASA, John H Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 6 TC 5 Z9 5 U1 1 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 4 BP 443 EP 452 PG 10 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85P UT WOS:000183408400053 ER PT S AU Zhu, DM Choi, SR Miller, RA AF Zhu, DM Choi, SR Miller, RA BE Singh, M Jessen, T TI Thermal fatigue and fracture behavior of ceramic thermal barrier coatings SO 25TH ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 25th Annual Conference on Composites, Advanced Ceramics, Materials and Structures CY JAN 21-27, 2001 CL COCOA BEACH, FL SP Amer Ceram Soc ID TEMPERATURE DEFORMATION AB Thermal fatigue and fracture behavior of plasma-sprayed ceramic thermal barrier coatings has been investigated under high heat flux and thermal cyclic conditions. The coating crack propagation is studied under laser heat flux cyclic thermal loading, and is correlated with dynamic fatigue and strength test results. The coating stress response and inelasticity, fatigue and creep interactions, and interface damage mechanisms during dynamic thermal fatigue processes are emphasized. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Zhu, DM (reprint author), NASA, Glenn Res Ctr, Lewis Field, Cleveland, OH 44135 USA. NR 17 TC 5 Z9 5 U1 1 U2 3 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2001 VL 22 IS 4 BP 453 EP 461 PG 9 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Composites SC Engineering; Materials Science GA BW85P UT WOS:000183408400054 ER PT B AU Dowding, J Hockey, BA Gawron, JM Culy, C AF Dowding, J Hockey, BA Gawron, JM Culy, C GP ACL TI Practical issues in compiling typed unification grammars for speech recognition SO 39TH ANNUAL MEETING OF THE ASSOCIATION FOR COMPUTATIONAL LINGUISTICS, PROCEEDINGS OF THE CONFERENCE LA English DT Proceedings Paper CT 39th Annual Meeting of the Association-for-Computational-Linguistics CY JUL 09-11, 2001 CL Toulouse, FRANCE SP Assoc Computat Linguist, CNRS, IRIT, Univ Sci Sociales, Univ Paul Sabatier, ATALA, ELSNET, Minist Educ Natl & Rech, Ctr Linguist & Computacio, Ville Toulouse, Conseil Reg Midi Pyrenees, Air France, EDF, France Telecom, IBM, Microsoft, Synapse Dev, Xerox Res Ctr AB Current alternatives for language modeling are statistical techniques based on large amounts of training data, and hand-crafted context-free or finite-state grammars that are difficult to build and maintain. One way to address the problems of the grammar-based approach is to compile recognition grammars from grammars written in a more expressive formalism. While theoretically straight-forward, the compilation process can exceed memory and time bounds, and might not always result in accurate and efficient speech recognition. We will describe and evaluate two approaches to this compilation problem. We will also describe and evaluate additional techniques to reduce the structural ambiguity of the language model. C1 NASA, Ames Res Ctr, RIACS RIALIST Grp, Moffett Field, CA 94035 USA. NR 25 TC 0 Z9 0 U1 0 U2 0 PU ASSOCIATION COMPUTATIONAL LINGUISTICS PI SOMERSET PA PO BOX 6090, SOMERSET, NJ 08875 USA BN 1-55860-767-6 PY 2001 BP 164 EP 171 PG 8 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Linguistics SC Computer Science; Linguistics GA BAR58 UT WOS:000223267600021 ER PT S AU Rutishauser, DK O'Connor, CJ AF Rutishauser, DK O'Connor, CJ GP ATCA ATCA TI The NASA aircraft VOrtex spacing system (AVOSS): Concept demonstration results and future direction SO 46TH ANNUAL AIR TRAFFIC CONTROL ASSOCIATION CONFERENCE PROCEEDINGS, FALL 2001 SE AIR TRAFFIC CONTROL ASSOCIATION, FALL CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 46th Annual Air-Traffic-Control-Association Conference CY NOV 04-08, 2001 CL WASHINGTON, D.C. SP Air Traffic Control Assoc C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Rutishauser, DK (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AIR TRAFFIC CONTROL ASSOC PI ARLINGTON PA 2300 CLAREDON BLVD, SUITE 711, ARLINGTON, VA 22201 USA SN 0192-8740 J9 ATCA CONF P PY 2001 BP 12 EP 16 PG 5 WC Automation & Control Systems; Transportation; Transportation Science & Technology SC Automation & Control Systems; Transportation GA BV01D UT WOS:000177596700003 ER PT S AU Nguyen, DH Skladnay, LM Prats, BD AF Nguyen, DH Skladnay, LM Prats, BD BE Schurmann, B TI Thermal performance of the Hubble Space Telescope (HST) Solar Array-3 during the Disturbance Verification Test (DVT) SO 4TH INTERNATIONAL SYMPOSIUM ON ENVIRONMENTAL TESTING FOR SPACE PROGRAMMES, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 4th International Symposium on Environmental Testing for Space Programmes CY JUN 12-14, 2001 CL LIEGE, BELGIUM AB The Hubble Space Telescope (HST) is one of NASA's most productive astronomical observatories. Launched in 1990, the HST continues to gather scientific data to help scientists around the world discover amazing wonders of the universe. To maintain HST in the fore front of scientific discoveries, NASA has routinely conducted servicing missions to refurbish older equipment as well as to replace existing scientific instruments with better, more powerful instruments. In early 2002, NASA will conduct its fourth servicing mission to the HST. This servicing mission is named Servicing Mission 3B (SM3B). During SM3B, one of the major refurbishment efforts will be to install new rigid-panel solar arrays as a replacement for the existing flexible-foil solar arrays. This is necessary in order to increase electrical power availability for the new scientific instruments. Prior to installing the new solar arrays on HST, the HST project must be certain that the new solar arrays will not cause any performance degradations to the observatory. One of the major concerns is any disturbance that can cause pointing Loss of Lock (LOL) for the telescope. While in orbit, the solar-array temperature transitions quickly from sun to shadow. The resulting thermal expansion and contraction can cause a "mechanical disturbance" which may result in LOL. To better characterize this behavior, a test was conducted at the European Space Research and Technology Centre (ESTEC) in the Large Space Simulator (LSS) thermal-vacuum chamber. In this test, the Sun simulator was used to simulate on-orbit effects on the solar arrays. This paper summarizes the thermal performance of the Solar Array-3 (SA3) during the Disturbance Verification Test (DVT). The test was conducted between 26 October 2000 and 30 October 2000. Included in this paper are: A brief description of the SA3's components and its thermal design; A summary of the on-orbit temperature predictions; Pretest thermal preparations; A description of the chamber and thermal monitoring sensors; Presentation of test thermal data results versus flight predictions. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Nguyen, DH (reprint author), NASA, Goddard Space Flight Ctr, Code 545, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-709-7 J9 ESA SP PUBL PY 2001 VL 467 BP 165 EP 170 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT29V UT WOS:000172547400022 ER PT S AU Hoffman, AR Larson, TW Avila, A AF Hoffman, AR Larson, TW Avila, A BE Schurmann, B TI Assessment of the effectiveness of prelaunch temperature testing and analysis for unmanned outer planet spacecraft SO 4TH INTERNATIONAL SYMPOSIUM ON ENVIRONMENTAL TESTING FOR SPACE PROGRAMMES, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 4th International Symposium on Environmental Testing for Space Programmes CY JUN 12-14, 2001 CL LIEGE, BELGIUM AB In the last 30 years, seven unmanned planetary spacecraft have been designed, ground tested and flown to astronomical distances of five astronomical units (5 AU) and beyond. These missions include flybys, planetary, orbiters and atmospheric probes. The thermal design approach applied to these spacecraft is based on the passive thermal designs applied to earlier lunar and interplanetary spacecraft. The ground test and analysis programs are also based on that heritage. The in-flight temperature data from representative sets of engineering subsystems and science instruments from four of these spacecraft are compared to those obtained during the ground test programs and from the prelaunch predictions. Recommendations for new projects to aid in the planning of cost-effective temperature design, test and analysis programs are presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hoffman, AR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-709-7 J9 ESA SP PUBL PY 2001 VL 467 BP 467 EP 475 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT29V UT WOS:000172547400067 ER PT S AU Ghaffarian, R AF Ghaffarian, R GP IEEE IEEE TI Effect of thermal cycling ramp rate on CSP assembly reliability SO 51ST ELECTRONIC COMPONENTS & TECHNOLOGY CONFERENCE SE Electronic Components and Technology Conference LA English DT Proceedings Paper CT 51st Electronic Components and Technology Conference (ECTC) CY MAY 29-JUN 01, 2001 CL ORLANDO, FL SP IEEE Components, Packaging & Mfg Technol Soc, Electr Components, Assemblies & Mat Assoc AB A JPL-led chip scale package (CSP) Consortium of enterprises, composed of team members representing government agencies and private companies, recently joined together to pool in-kind resources for developing the quality and reliability of chip scale packages (CSPs) for a variety of projects. The experience of the Consortium in building more than 150 test vehicle assemblies, single- and double-sided multilayer PWBs, and the environmental test results has now been published as a chip scale package (CSP)guidelines document and distributed by Interconnection Technology Research Institute (ITRI). The Consortium assembled fifteen different packages with I/Os from 48 to 784 and pitches from 0.5 to 1.27 mm on multilayer FR-4 printed wiring board (PWB). Another test vehicle was designed and assembled by a team member using their internal resources and was identified as m-H. The TV-H assemblies were subjected to numerous thermal cycling conditions including -55 degreesC to 125 degreesC with two ramp rates, one thermal cycle with 2 degrees to 5 degreesC/min and the other near thermal shock. Cycles-to-failure (CTF) test results to 1,000 cycles and 400 cycles under these conditions are presented for fine pitch ball grid arrays (FPBGAs), CSPs, and wafer level CSPs (WLCSPs). Decrease in CTFs due to ramp rate and die size increase for different I/O FPBGAs with 0.8 mm pitch are compared and analyzed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM Reza.Ghaffarian@JPL.NASA.Gov NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0569-5503 BN 0-7803-7038-4 J9 ELEC COMP C PY 2001 BP 1170 EP 1174 DI 10.1109/ECTC.2001.927974 PG 5 WC Engineering, Manufacturing; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Optics SC Engineering; Materials Science; Optics GA BS31N UT WOS:000169430500194 ER PT B AU Cukic, B AF Cukic, B GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI The need for verification and validation techniques for adaptive control system SO 5TH INTERNATIONAL SYMPOSIUM ON AUTONOMOUS DECENTRALIZED SYSTEMS, PROCEEDINGS LA English DT Proceedings Paper CT 5th IEEE International Symposium on Autonomous Decentralized Systems (ISADS 01) CY MAR 26-28, 2001 CL DALLAS, TX SP IEEE Comp Soc, Tech Comm Distributed Processing, Informat Processing Soc Japan, Soc Instrument & Control Engineers Japan, Inst Electr, Informat, & Commun Engineers Japan, Int Federat Informat Processing, Int Federat Automat Control, OMG, TINA C, Mfg Sci & Technol Ctr, Japan C1 W Virginia Univ, Dept Comp Sci & Elect Engn, NASA, WVU Software Res Lab, Morgantown, WV 26506 USA. RP Cukic, B (reprint author), W Virginia Univ, Dept Comp Sci & Elect Engn, NASA, WVU Software Res Lab, Morgantown, WV 26506 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1065-5 PY 2001 BP 297 EP 298 PG 2 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems SC Computer Science GA BS28C UT WOS:000169357200042 ER PT B AU DeCoste, D AF DeCoste, D BE Zhang, L Gu, F TI Visualizing mercer kernel feature spaces via kernelized locally-linear embeddings SO 8TH INTERNATIONAL CONFERENCE ON NEURAL INFORMATION PROCESSING, VOLS 1-3, PROCEEDING LA English DT Proceedings Paper CT 8th International Conference on Neural Information Processing (ICONIP 2001) CY NOV 14-18, 2001 CL SHANGHAI, PEOPLES R CHINA SP Asia-Pacific Neural Network Assembly, China Neural Network Council, Fundan Univ, Shanghai Assoc Sci & Technol, IEEE Beijing Sect, IEEE NN Council INNS, Fudan Univ, Ctr Brain Sci Res, Shanghai Soc Biophys AB A new technique for projecting high-dimensional data to low-dimensional spaces, called locally linear embedding (LLE), has recently been introduced. LLE offers many benefits over traditional alternatives, such as principal component analysis (PCA) and multi-dimensional scaling (MDS). In this paper, we generalize LLE to use Mercer kernels, resulting in a method we call KLLE. Mercer kernels have recently become very popular, due in large part to many recent successes in applying kernel methods such as support vector machines (SVMs) and kernel PCA to many real world problems. KLLE provides a powerful new tool for visualizing how Mercer kernels (implicitly) project data from input space to kernel feature space, which is an open and critical issue for better understanding how kernel methods work and how to best apply them. C1 CALTECH, Jet Prop Lab, Machine Learning Syst Grp, Pasadena, CA 91109 USA. RP DeCoste, D (reprint author), CALTECH, Jet Prop Lab, Machine Learning Syst Grp, 4800 Oak Grove Dr,M-S 126-347, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 1 PU FUDAN UNIV PRESS PI SHANGHAI PA 579 GUOQUAN RD, SHANGHAI 200433, PEOPLES R CHINA BN 7-309-03012-5 PY 2001 BP 867 EP 872 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Hardware & Architecture; Robotics SC Computer Science; Robotics GA BU46F UT WOS:000176058200153 ER PT S AU Jones, WR Jansen, MJ Gschwender, LJ Snyder, CE Sharma, SK Predmore, RE Dube, MJ AF Jones, WR Jansen, MJ Gschwender, LJ Snyder, CE Sharma, SK Predmore, RE Dube, MJ BE Harris, RA TI The tribological properties of several silahydrocarbons for use in space mechanisms SO 9TH EUROPEAN SPACE MECHANISMS AND TRIBOLOGY SYMPOSIUM SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 9th European Space Mechanisms and Tribology Symposium CY SEP 19-21, 2001 CL LIEGE, BELGIUM SP European Space Agcy, Univ Liege, OSTC, CNES, DLR, Techspace Aero ID POLYSILAHYDROCARBON SYNTHETIC FLUIDS; LUBRICANTS AB Silahydrocarbons are members of a relatively new class of liquid lubricants with great potential for use in space mechanisms, They are unimolecular species consisting of silicon, carbon and hydrogen. They possess unique wear, viscosity and volatility properties while retaining the ability to solubilize conventional additives. The tribological properties of several members of this class, including tri-, tetra- and penta-compounds, are presented. These properties include: viscosity-temperature, viscosity-pressure, vapor pressure, lubricant lifetimes, traction, reciprocating and four ball wear rates. Lubricant lifetimes were determined using a vacuum ball bearing simulator, the spiral orbit tribometer (SOT). Wear was measured using a Cameron Plint reciprocating tribometer and wear rates with a vacuum four ball tribometer. Conventional viscometry was used for viscosity-temperature measurements and a Knudsen cell for vapor pressure. Thermogravimetric Analysis (TGA) was also used for volatility measurements. Pressure viscosity coefficients (alpha values) were estimated from EBL film thickness measurements. These properties are compared to existing state-of-the-art space lubricants. C1 NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Jones, WR (reprint author), NASA, John H Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 17 TC 0 Z9 0 U1 1 U2 2 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-761-5 J9 ESA SP PUBL PY 2001 VL 480 BP 57 EP 63 PG 7 WC Engineering, Aerospace; Engineering, Mechanical SC Engineering GA BT57A UT WOS:000173394800008 ER PT S AU Stewart, AC AF Stewart, AC BE Harris, RA TI A new and innovative use of the thermal knife and Kevlar cord components in a restraint and release system SO 9TH EUROPEAN SPACE MECHANISMS AND TRIBOLOGY SYMPOSIUM SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 9th European Space Mechanisms and Tribology Symposium CY SEP 19-21, 2001 CL LIEGE, BELGIUM SP European Space Agcy, Univ Liege, OSTC, CNES, DLR, Techspace Aero AB A Kevlar cord and two thermal knives are key components in the Solar Array Restraint and Release System (SARRS) on the Microwave Anisotropy Probe (MAP) spacecraft at NASA's Goddard Space Flight Center. The SARRS uses a 25-foot (7.62 m) length Kevlar cord that encircles the spacecraft and secures the solar panels in stowed configuration for launch. Once in orbit, one of two redundantly configured thermal knives severs the Kevlar cord and permits the panels to deploy. The purpose of this paper is to present the details of the design, development test results, and the various innovations that were created during the development of this novel use of the thermal knife and Kevlar cord. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Stewart, AC (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 1 TC 0 Z9 0 U1 0 U2 2 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-761-5 J9 ESA SP PUBL PY 2001 VL 480 BP 231 EP 238 PG 8 WC Engineering, Aerospace; Engineering, Mechanical SC Engineering GA BT57A UT WOS:000173394800029 ER PT S AU Rakoczy, J Hall, D Howard, R Weir, J Montgomery, E Ames, G Danielson, T Zercher, P AF Rakoczy, J Hall, D Howard, R Weir, J Montgomery, E Ames, G Danielson, T Zercher, P BE Tyson, RK Bonaccini, D Roggemann, MC TI Demonstration of a segment alignment maintenance system on a seven-segment sub-array of the Hobby-Eberly Telescope SO ADAPTIVE OPTICS SYSTEMS AND TECHNOLOGY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Adaptive Optics Systems and Technology II CY JUL 30-AUG 01, 2001 CL SAN DIEGO, CA SP SPIE DE edge sensors; figure maintenance; segmented mirrors; active optics AB NASA's Marshall Space Flight Center, in collaboration with Blue Line Engineering of Colorado Springs, Colorado, is developing a Segment Alignment Maintenance System (SAMS) for McDonald Observatory's Hobby-Eberly Telescope (HET). The SAMS shall sense motions of the 91 primary mirror segments and send corrections to HET's primary mirror controller as the mirror segments misalign due to thermo-elastic deformations of the mirror support structure. The SAMS consists of inductive edge sensors. All measurements are sent to the SAMS computer where mirror motion corrections are calculated. In October 2000, a prototype SAMS was installed on a seven-segment cluster of the HET. Subsequent testing has shown that the SAMS concept and architecture are a viable practical approach to maintaining HET's primary mirror figure, or the figure of any large segmented telescope. This paper gives a functional description of the SAMS sub-array components and presents test data to characterize the performance of the sub-array SAMS. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Rakoczy, J (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4208-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4494 BP 69 EP 80 AR UNSP 4494-10 PG 12 WC Instruments & Instrumentation; Remote Sensing; Optics; Physics, Applied SC Instruments & Instrumentation; Remote Sensing; Optics; Physics GA BU15M UT WOS:000175163000008 ER PT S AU Milos, FS Watters, DG Pallix, JB Bahr, AJ Huestis, DL AF Milos, FS Watters, DG Pallix, JB Bahr, AJ Huestis, DL BE Kundu, T TI Wireless subsurface microsensors for health monitoring of thermal protection systems on hypersonic vehicles SO ADVANCED NONDESTRUCTIVE EVALUATION FOR STRUCTURAL AND BIOLOGICAL HEALTH MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advanced Nondestructive Evaluation for Structural and Biological Health Monitoring CY MAR 06-08, 2001 CL NEWPORT BEACH, CA SP SPIE DE damage detection; embedded sensor; health monitoring; nondestructive evaluation; RFID; SensorTag; smart materials; thermal protection systems; wireless communications AB Health diagnostics is an area where major improvements have been identified for potential implementation into the design of new reusable launch vehicles in order to reduce life cycle costs, to increase safety margins, and to improve mission reliability. NASA Ames is leading the effort to develop inspection and health management technologies for thermal protection systems. This paper summarizes a joint project between NASA Ames and SRI International to develop "SensorTags," radio-frequency identification devices coupled with event-recording sensors, that can be embedded in the thermal protection system to monitor temperature or other quantities of interest, Two prototype SensorTag designs containing thermal fuses to indicate a temperature overlimit are presented and discussed. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Milos, FS (reprint author), NASA, Ames Res Ctr, MS 234-1, Moffett Field, CA 94035 USA. NR 9 TC 3 Z9 3 U1 1 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4021-3 J9 P SOC PHOTO-OPT INS PY 2001 VL 4335 BP 74 EP 82 DI 10.1117/12.434159 PG 9 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BU37T UT WOS:000175830100009 ER PT S AU Bar-Cohen, Y Bao, XQ Dolgin, B Marzwell, N AF Bar-Cohen, Y Bao, XQ Dolgin, B Marzwell, N BE Kundu, T TI Residue detection for real-time removal of paint from metallic surfaces SO ADVANCED NONDESTRUCTIVE EVALUATION FOR STRUCTURAL AND BIOLOGICAL HEALTH MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advanced Nondestructive Evaluation for Structural and Biological Health Monitoring CY MAR 06-08, 2001 CL NEWPORT BEACH, CA SP SPIE DE NDE; NDT; paint; real-time testing; sensors; robotics; marine; paint stripping; waterjet feedback AB Paint stripping from large steel ships and other metallic surfaces is a major environmental safety, cost, and operational challenge in effectively and efficiently maintaining and refurbishing large structures. Environmental concerns are greatly limiting the possible options. As a result, a hybrid system composed of a waterjet with water recycling and robotic mobile manipulators with scanning bridges has become the leading form of paint stripping and was constructed by various manufacturers to address this need. The application of such scanning bridges is slow and their access is constrained by the complex shape of the ship hull and various features on the surface. To overcome these limitations, a robotic system that is called UltraStrip (UltraStrip Systems, Inc., Stuart, FL) is developed. This system uses magnetic wheels to attach the stripper to the structure and travel on it while performing paint stripping. To assure efficient paint stripping feedback data is required to control the travel speed by monitoring the paint thickness before and during the stripping process. Efforts at JPL are currently underway to develop the required feedback capability to assure effective paint stripping. Various possible sensors were considered and issues that can affect the sensitivity, reliability and applicability of the sensors are being investigated with emphasis on measuring the initial conditions of the paint. Issues that affect the sensory data in dynamic conditions are addressed while providing real-time real feedback for the control of the paint stripper speed of travel. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 1 Z9 1 U1 0 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4021-3 J9 P SOC PHOTO-OPT INS PY 2001 VL 4335 BP 115 EP 120 DI 10.1117/12.434165 PG 6 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BU37T UT WOS:000175830100014 ER PT B AU Jones, HP Ceja, JA AF Jones, HP Ceja, JA BE Sigwarth, M TI Preliminary comparison of magnetograms from KPVT/SPM, SOHO/MDI and GONG(+) SO ADVANCED SOLAR POLARIMETRY: THEORY, OBSERVATION, AND INSTRUMENTA TION SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 20th International National-Solar-Obervatory/Sacramento Peak Summer Workshop on Advanced Solar Polarimetry Theory, Observation, and Instrumentation CY SEP 11-15, 2000 CL NATL SOLAR OBERVAT, SUNSPOT, NM SP Natl Sci Fdn, Div Astron & Atmospher Sci, NASA, Off Space Sci, Air Force Sci Res, European Off Aerosp Res & Dev, Asian Off Aerosp Res & Dev HO NATL SOLAR OBERVAT ID SPECTROMAGNETOGRAPH AB As part of a program to establish a continuous flux scale between magnetograms taken with the SOLIS Vector Spectromagnetograph (VSM) and the 25-year set of National Solar Observatory/Kitt Peak Vacuum Telescope (NSO/KPVT) magnetograms, we have compared data taken with the NASA/NSO Spectromagnetograph (SPM) at the KPVT to Solar and Heliospheric Observatory/Michelson-Doppler Imager (SOHO/MDI) and improved Global Oscillations Network Group (GONG(+)) magnetograms. Our purposes are to make sure that tools are in place for a similar comparison between the VSM and SPM, to establish the flux-comparison formulas for the three instruments, and to provide back-up data in case circumstances prevent a future direct comparison between the VSM and the SPM. We compare a large number of images with a fast histogram equating method which takes specific account of the power-law nature of magnetographic histograms and which does not require precise image registration. We also show pixel-by-pixel comparisons of a subset of these images to illustrate the efficacy of histogram equating. Preliminary results indicate that the scales of measurement (flux-equivalent Gauss) for GONG+ and SPM magnetograms agree with each other and should be multiplied by a factor of about 1.4 to correspond with MDI. C1 NASA, Goddard Space Flight Ctr, Lab Astron & Solar Phys, SW Solar Stn,Natl Solar Observ, Tucson, AZ 85726 USA. RP Jones, HP (reprint author), NASA, Goddard Space Flight Ctr, Lab Astron & Solar Phys, SW Solar Stn,Natl Solar Observ, POB 26732, Tucson, AZ 85726 USA. NR 7 TC 15 Z9 15 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-073-0 J9 ASTR SOC P PY 2001 VL 236 BP 87 EP 93 PG 7 WC Engineering, Aerospace; Spectroscopy SC Engineering; Spectroscopy GA BU41F UT WOS:000175937600012 ER PT B AU Jennings, DE Deming, D Sada, PV McCabe, GH Moran, T AF Jennings, DE Deming, D Sada, PV McCabe, GH Moran, T BE Sigwarth, M TI Mapping of vector magnetic fields at 12 mu m SO ADVANCED SOLAR POLARIMETRY: THEORY, OBSERVATION, AND INSTRUMENTA TION SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT 20th International National-Solar-Obervatory/Sacramento Peak Summer Workshop on Advanced Solar Polarimetry Theory, Observation, and Instrumentation CY SEP 11-15, 2000 CL NATL SOLAR OBERVAT, SUNSPOT, NM SP Natl Sci Fdn, Div Astron & Atmospher Sci, NASA, Off Space Sci, Air Force Sci Res, European Off Aerosp Res & Dev, Asian Off Aerosp Res & Dev HO NATL SOLAR OBERVAT ID MICRON EMISSION-LINES; MG-I; LIMB OBSERVATIONS; INFRARED LINES; FEATURES; ECLIPSE; DIAGNOSTICS; SUNSPOTS; PROBES AB Infrared Stokes polarimetry of solar magnetic fields have begun to play a important role in understanding structures in the photosphere. The Celeste high-resolution cryogenic grating spectrometer, developed at Goddard Space Flight Center and used at the McMath-Pierce Telescope, has recently been applied to mapping Stokes profiles at 12 mum. The 12.3 mum MgI emission line has the advantage for magnetic field observations that its Zeeman components are often resolvable down to field strengths of a few hundred gauss. Full 12 mum maps of Stokes parameters have been recorded in sunspots. C1 NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Greenbelt, MD 20771 USA. RP Jennings, DE (reprint author), NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Greenbelt, MD 20771 USA. RI Jennings, Donald/D-7978-2012 NR 22 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-073-0 J9 ASTR SOC P PY 2001 VL 236 BP 273 EP 280 PG 8 WC Engineering, Aerospace; Spectroscopy SC Engineering; Spectroscopy GA BU41F UT WOS:000175937600029 ER PT S AU Barnes, NP Clarkson, WA Hanna, DC Turner, PW Nilsson, J Walsh, BM AF Barnes, NP Clarkson, WA Hanna, DC Turner, PW Nilsson, J Walsh, BM BE Marshall, C TI Diode pumped, tunable, Q-switched Tm : glass fiber laser SO ADVANCED SOLID-STATE LASERS, PROCEEDINGS SE OSA TRENDS IN OPTICS AND PHOTONICS LA English DT Proceedings Paper CT Topical Meeting on Advanced Solid-State Lasers CY JAN 28-31, 2001 CL SEATTLE, WA SP Opt Soc Amer, IEEE, Lasers & Electro Opt Soc AB A tunable, Q-switched Tm:glass fiber produced >100 mW, >40 muJ at 2.8 kHz, in a single pulse and 300 mW in multiple pulses. Wavelength and multiple pulsing depended on several spectroscopic, pumping, and Q-switching parameters. Needed spectroscopic parameters are measured and used in laser models to interpret experimental results. OCIS codes: (140.3480) Lasers, diode pumped; (140.3540) Lasers, Q-switched. C1 NASA Langley Res Ctr, Hampton, VA 23681 USA. NR 2 TC 2 Z9 2 U1 1 U2 2 PU OPTICAL SOC AMERICA PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-5695 BN 1-55752-661-3 J9 OSA TRENDS OPT PHOTO PY 2001 VL 50 BP 88 EP 95 PG 8 WC Optics; Physics, Applied SC Optics; Physics GA BT71R UT WOS:000173833500020 ER PT S AU Yu, JR Petros, M Singh, UN Barnes, JC Barnes, NP AF Yu, JR Petros, M Singh, UN Barnes, JC Barnes, NP BE Marshall, C TI A high energy double pulsed Ho : Tm : YLF 2-mu m laser SO ADVANCED SOLID-STATE LASERS, PROCEEDINGS SE OSA TRENDS IN OPTICS AND PHOTONICS LA English DT Proceedings Paper CT Topical Meeting on Advanced Solid-State Lasers CY JAN 28-31, 2001 CL SEATTLE, WA SP Opt Soc Amer, IEEE, Lasers & Electro Opt Soc AB We describe an innovative double-pulsed Ho:Tm:YLF 2-mum laser. This laser takes advantage of the Tm:Ho energy sharing process to utilize the pump energy efficiently. It has a great application in Differential Absorption Lidar. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Yu, JR (reprint author), NASA, Langley Res Ctr, MS 474, Hampton, VA 23681 USA. NR 8 TC 2 Z9 2 U1 1 U2 3 PU OPTICAL SOC AMERICA PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-5695 BN 1-55752-661-3 J9 OSA TRENDS OPT PHOTO PY 2001 VL 50 BP 383 EP 387 PG 5 WC Optics; Physics, Applied SC Optics; Physics GA BT71R UT WOS:000173833500081 ER PT J AU Zhou, YP Rutledge, KC Charlock, TP Loeb, NG Kato, S AF Zhou, YP Rutledge, KC Charlock, TP Loeb, NG Kato, S TI Atmospheric corrections using MODTRAN for TOA and surface BRDF characteristics from high resolution spectroradiometric/angular measurements from a helicopter platform SO ADVANCES IN ATMOSPHERIC SCIENCES LA English DT Article; Proceedings Paper CT International Conference on Climate and Environment Variability and Predictability (CEVP) CY AUG 07-11, 2000 CL SHANGHAI, PEOPLES R CHINA SP Atmospher Sci & Geophys Fluid Dynam, Natl Key Lab, Inst Atmospher Phys, Chinese Acad Sci DE BRDF; radiative transfer; atmospheric correction ID BIDIRECTIONAL REFLECTANCE; SATELLITE DATA; RETRIEVAL; RADIATION; PRAIRIE; MODELS AB High-resolution spectral radiance measurements were taken by a spectral radiometer on board a helicopter over the US Oklahoma Southern Great Plain near the Atmospheric Radiation Measurements (ARM) site during August 1998. The radiometer has a spectral range from 350 nm to 2500 nm at 1 nm resolution. The measurements covered several grass and cropland scene types at multiple solar zenith angles. Detailed atmospheric corrections using the Moderate Resolution Transmittance (MODTRAN) radiation model and in-situ sounding and aerosol measurements have been applied to the helicopter measurements in order to retrieve the surface and top of atmosphere (TOA) Bidirectional Reflectance Distribution Function (BRDF) characteristics. The atmospheric corrections are most significant in the visible wavelengths and in the strong water vapor absorption wavelengths in the near infrared region. Adjusting the BRDF to TOA requires a larger correction in the visible channels since Rayleigh scattering contributes significantly to the TOA reflectance. The opposite corrections to the visible and near infrarred wavelengths can alter the radiance difference and ratio that many remote sensing techniques are based on, such as the normalized difference vegetation index (NDVI). The data show that surface BRDFs and spectral albedos are highly sensitive to the vegetation type and solar zenith angle while BRDF at TOA depends more on atmospheric conditions and the vi ewing geometry. Comparison with the Clouds and the Earth's Radiant Energy System (CERES) derived clear sky Angular Distribution Model (ADM) for crop and grass scene type shows a standard deviation of 0.08 in broadband anisotropic function at 25 degrees solar zenith angle and 0.15 at 50 degrees solar zenith angle, respectively. C1 Analyt Serv & Mat Inc, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23665 USA. Hampton Univ, Hampton, VA 23668 USA. RP Zhou, YP (reprint author), NOAA, WWB, NWS, NCEP,Climate Predict Ctr,Anal Branch, 5200 Auth Rd, Camp Springs, MD 20746 USA. RI AAS, AAS/C-2949-2014 NR 24 TC 3 Z9 3 U1 1 U2 2 PU CHINA OCEAN PRESS PI BEIJING PA INTERNATIONAL DEPT, 8 DA HUI SHI, BEIJING 100081, PEOPLES R CHINA SN 0256-1530 J9 ADV ATMOS SCI JI Adv. Atmos. Sci. PY 2001 VL 18 IS 5 BP 984 EP 1004 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 475VN UT WOS:000171190400029 ER PT S AU Tsurutani, BT Arballo, JK Galvan, C Zhang, LD Lakhina, GS Hada, T Pickett, JS Gurnett, DA AF Tsurutani, BT Arballo, JK Galvan, C Zhang, LD Lakhina, GS Hada, T Pickett, JS Gurnett, DA BE Malingre, M TI Auroral zone plasma waves detected at polar: PCBL waves SO ADVANCES IN AURORAL PHYSICS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D3 2 Symposium of COSPAR Scientific Commission D held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Amer Geophys Union, Ctr Natl Etud Spatiales, Int Union Radio Sci, Int Union Geodesy & Geophys, Int Assoc Geomagnet Aeronom, Comm Space Res ID MAGNETOPAUSE BOUNDARY-LAYER; DIFFUSION-PROCESSES; TURBULENCE AB Polar Cap Boundary Layer waves are ELF/VLF electric and magnetic waves detected on field lines adjacent to the polar cap, thus their name. Waves are present at this location 96% of the time. The wave latitude-local time distribution is shown to be the same as that of the auroral oval. The most intense waves are detected coincident with the strongest magnetic field gradients (field-aligned currents). Specific frequency bands of whistler mode-waves are identified: similar to200 Hz, 1-2 kHz and similar to5 kHz. Two types of intense electric waves are present: solitary bipolar pulses (electron holes) and similar tokHz electric turbulence. The PCBL waves are most likely a consequence of auroral zone field-aligned current instabilities. The currents have in turn been ascribed to be due to magnetospheric convection driven by the solar wind. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Indian Inst Technol, Mumbai 400005, India. Kyushu Univ, Fukuoka 8168580, Japan. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. RP Tsurutani, BT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Lakhina, Gurbax /C-9295-2012; OI Lakhina, Gurbax /0000-0002-8956-486X NR 20 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 28 IS 11 BP 1655 EP 1659 DI 10.1016/S0273-1177(01)00483-5 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT60P UT WOS:000173496800012 ER PT B AU Chernov, AA AF Chernov, AA BE Sato, K Furukawa, Y Nakajima, K TI Challenges in crystal growth science and the microgravity tool SO ADVANCES IN CRYSTAL GROWTH RESEARCH LA English DT Proceedings Paper CT 11th International Summer School on Crystal Growth (ISSCG-11) CY JUL 24-29, 2001 CL SHIGA, JAPAN SP Japan Sco Appl Phys, Int Union Crystallog, Japanese Assoc Crystal Growth, Doshisha Univ, Ase Inc ID ATOMIC-FORCE MICROSCOPY; SURFACE-MORPHOLOGY; PROTEIN; CRYSTALLIZATION; SOLIDIFICATION; KINETICS; NUCLEATION; THAUMATIN; VIRUS; FACE AB Selected scientific topics where microgravity experiments help to solve general problems of crystal growth science are discussed. These are coupling between interface kinetics, diffusion and convection mass transport, dendritic growth, pattern formation, detached growth and crystal perfection. Specific attention is paid to biomacromolecular crystallization. Recent findings show that at least some of the crystals grown in space are purer than their terrestrial counterparts. This may open the way to faster move of the biocrystallization area from art to science and help to eliminate ever-narrowing bottleneck for development of structural biology. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35806 USA. RP Chernov, AA (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, 4950 Corp Dr,Suite 100, Huntsville, AL 35806 USA. NR 77 TC 1 Z9 1 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS BN 0-444-50747-7 PY 2001 BP 62 EP 77 DI 10.1016/B978-044450747-1/50031-4 PG 4 WC Crystallography SC Crystallography GA BS92R UT WOS:000171392500004 ER PT J AU Wasfy, TM Noor, AK AF Wasfy, TM Noor, AK TI Object-oriented virtual environment for visualization of flexible multibody systems SO ADVANCES IN ENGINEERING SOFTWARE LA English DT Article DE virtual environment; flexible multibody systems; finite elements ID REALITY; PERFORMANCE; SIMULATIONS; ISSUES AB An object-oriented event-driven virtual environment (VE) for viewing the simulation results of flexible multibody systems (FMS) is developed. The VE interfaces with the following output devices: immersive stereoscopic screen(s) and stereo speakers; and a variety of input devices including, head tracker, wand, joystick, mouse, microphone, and keyboard. The VE incorporates the following types of primitive software objects: user-interface objects, support objects, geometric entities, and finite elements. Each object encapsulates a set of properties, methods, and events that define its behavior, appearance, and functions. A "container" object allows grouping many objects into one object, which inherits the properties of its "children" objects. The VE allows real-time viewing and "fly-through" of photo-realistic models, vibrational mode-shapes, and animation of the dynamic motion of FMS. An application of this VE is presented for visualization of the dynamic analysis results of a large deployable space structure - NASA's Next Generation Space Telescope. Published by Elsevier Science Ltd. C1 NASA, Langley Res Ctr, Ctr Adv Comp Technol, Hampton, VA 23681 USA. RP Noor, AK (reprint author), NASA, Langley Res Ctr, Ctr Adv Comp Technol, Mail Stop 201, Hampton, VA 23681 USA. NR 40 TC 9 Z9 10 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0965-9978 J9 ADV ENG SOFTW JI Adv. Eng. Softw. PY 2001 VL 32 IS 4 BP 295 EP 315 DI 10.1016/S0965-9978(00)00091-0 PG 21 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering; Engineering, Multidisciplinary SC Computer Science; Engineering GA 408BG UT WOS:000167306200004 ER PT S AU Park, B Eppler, DB AF Park, B Eppler, DB BE Clemesha, B TI Accommodations for earth-viewing payloads on the International Space Station SO ADVANCES IN REMOTE SENSING OF THE MIDDLE AND UPPER ATMOSPHERE AND THE IONOSPHERE SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT C2 7 Symposium COSPAR Scientific Commission C held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Amer Geophys Union, European Goephys Soc, Int Union Geodesy & Geophys, Int Assoc Geomagnet & Aeronom, IUGG, Int Assoc Meteorol, IUGG, Atmospher Sci, IUGG, Meteorol Middle Atomosphere, Comm Space Res AB The design of the International Space Station (ISS) includes payload locations that are external to the pressurized environment. These external or attached payload accommodation locations will allow direct access to the space environment at the ISS orbit and direct viewing of the earth and space. NASA sponsored payloads will have access to several different types of standard external locations; the S3 Truss Sites, the Columbus External Payload Facility (EPF), and the Japanese Experiment Module Exposed Facility (JEM-EF). As the ISS Program develops, it may also be possible to locate external payloads at the P3 Truss Sites or at non-standard locations similar to the handrail-attached payloads that were flown during the MIR Program. Earth-viewing payloads may also be located within the pressurized volume of the US Lab in the Window Observational Research Facility (WORF). Payload accommodations at each of the locations will be described, as well as transport to and retrieval from the site. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. SAIC, Houston, TX 77058 USA. RP Park, B (reprint author), NASA, Goddard Space Flight Ctr, Code 800-G, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 27 IS 6/7 BP 1057 EP 1063 DI 10.1016/S0273-1177(01)00138-7 PG 7 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT01P UT WOS:000171630300002 ER PT S AU Grimsley, BW Hubert, P Song, XL Cano, RJ Loos, AC Pipes, RB AF Grimsley, BW Hubert, P Song, XL Cano, RJ Loos, AC Pipes, RB BE Falcone, A Nelson, KM Albers, R Avery, WB TI Flow and compaction during the vacuum assisted resin transfer molding process SO ADVANCING AFFORDABLE MATERIALS TECHNOLOGY SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 33rd International SAMPE Technical Conference CY NOV 05-08, 2001 CL SEATTLE, WA SP Soc Advancement Mat & Process Engn, Seattle Chapter DE composites; VARTM; process modeling ID COMPOSITES; INFUSION; SCRIMP AB The flow of an epoxy resin and compaction behavior of carbon fiber preform during vacuum-assisted resin transfer molding (VARTM) infiltration was measured using an instrumented tool. Composite panels were fabricated by the VARTM process using SAERTEX(R)(2) multi-axial non-crimp carbon fiber fabric and the A.T.A.R.D. SI-ZG-5A epoxy resin. Resin pressure and preform thickness variation was measured during infiltration. The effects of the resin on the compaction behavior of the preform were measured. The local preform compaction during the infiltration is a combination of wetting and spring-back deformations. Flow front position computed by the 3DINFIL model was compared with the experimental data. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Grimsley, BW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 19 TC 8 Z9 8 U1 2 U2 3 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-91-3 J9 INT SAMPE TECH CONF PY 2001 VL 33 BP 140 EP 153 PG 14 WC Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BT76Y UT WOS:000173976200014 ER PT S AU Frazier, M Vaughan, JG Lackey, E AF Frazier, M Vaughan, JG Lackey, E BE Falcone, A Nelson, KM Albers, R Avery, WB TI Experimental examination of fatigue properties using self tapping screws for mechanical attachment to sandwich composite materials SO ADVANCING AFFORDABLE MATERIALS TECHNOLOGY SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 33rd International SAMPE Technical Conference CY NOV 05-08, 2001 CL SEATTLE, WA SP Soc Advancement Mat & Process Engn, Seattle Chapter DE sandwich composites; mechanical fasteners; fatigue properties AB An increase in the use of advanced composite materials to construct structures has highlighted the need for effective outfitting attachment methods. One such method uses mechanical fasteners, which provide an efficient means of mounting various types of equipment onto the composite structure, Data concerning the static and hygrothermal effects of a self-tapping screw/sandwich composite attachment method have been presented; however, fatigue data for this attachment method has not been discussed. Test specimens examined in this report consisted of a sandwich composite of two vinyl ester-glass laminate facesheets with a balsa core. Representative outfitting brackets were attached to the upper facesheet with four self-tapping screws. These brackets were then connected to a test Fixture, and a hydraulically operated testing machine was used to subject the samples to fatigue loading conditions. The fatigue samples were subjected to a minimum of 1,000,000 cycles at various loads in an attempt to cause failure. If the sample did not exhibit a fatigue failure prior to completion of at least 1,000,000 cycles, the fatigue test was stopped and a load-displacement plot was generated using a uniaxial static test to determine the effects of fatigue on the sample's properties. Results demonstrated a general decrease in panel stiffness throughout the test and that panels subjected to greater than 60% of the baseline uniaxial tension screw pullout load were more likely to fail than those at lower mean load levels. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Frazier, M (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-91-3 J9 INT SAMPE TECH CONF PY 2001 VL 33 BP 1195 EP 1208 PG 14 WC Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BT76Y UT WOS:000173976200105 ER PT S AU Grimsley, BW Cano, RJ Johnston, NJ Loos, AC McMahon, WM AF Grimsley, BW Cano, RJ Johnston, NJ Loos, AC McMahon, WM BE Falcone, A Nelson, KM Albers, R Avery, WB TI Hybrid composites for LH2 fuel tank structure SO ADVANCING AFFORDABLE MATERIALS TECHNOLOGY SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 33rd International SAMPE Technical Conference CY NOV 05-08, 2001 CL SEATTLE, WA SP Soc Advancement Mat & Process Engn, Seattle Chapter DE permeability; film; interleaf AB The application of lightweight carbon fiber reinforced plastics (CFRP) as structure for cryogenic fuel tanks is critical to the success of the next generation of Reusable Launch Vehicles (RLV). The recent failure of the X-33 composite fuel tank occurred in part due to microcracking of the polymer matrix, which allowed cryogen to permeate through the inner skin to the honeycomb core. As part of an approach to solve these problems, NASA Langley Research Center (LaRC) and Marshall Space Flight Center (MSFC) are working to develop and investigate polymer films that will act as a barrier to the permeation of LH2 through the composite laminate. In this study two commercially available films and eleven novel LaRC films were tested in an existing cryogenics laboratory at MSFC to deter-mine the permeance of argon at room temperature. Several of these films were introduced as a layer in the composite to form an interleaved, or hybrid, composite to determine the effects on permeability. In addition, the effects of the interleaved layer thickness, number, and location on the mechanical proper-tics of the composite laminate were investigated. In this initial screening process, several of the films were found to exhibit lower permeability to argon than the composite panels tested. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Grimsley, BW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 12 TC 2 Z9 2 U1 2 U2 4 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-91-3 J9 INT SAMPE TECH CONF PY 2001 VL 33 BP 1224 EP 1235 PG 12 WC Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BT76Y UT WOS:000173976200107 ER PT S AU Watson, KA Smith, JG Connell, JW AF Watson, KA Smith, JG Connell, JW BE Falcone, A Nelson, KM Albers, R Avery, WB TI Polyimide/carbon nanotube composite films for potential space applications SO ADVANCING AFFORDABLE MATERIALS TECHNOLOGY SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 33rd International SAMPE Technical Conference CY NOV 05-08, 2001 CL SEATTLE, WA SP Soc Advancement Mat & Process Engn, Seattle Chapter DE low color polyimides; atomic oxygen resistant polymers; phosphine oxide-containing films; polyimides; UV resistant polyimides; single wall carbon nanotubes.; nanocomposites; [2,4-Bis(3-aminophenoxy)phenyl]diplienylphosphine oxide ID CARBON NANOTUBES AB Polyimide/carbon nanotube composite films with a combination of properties including low color, atomic oxygen (AO) and ultra-violet (UV) radiation resistance, high g-lass transition temperatures, and high thermal stability have been prepared and characterized. Carbon nanotubes were added to the polymer in an attempt to impart sufficient electrical conductivity for static charge dissipation without increasing solar absorptivity. The polymer nanocomposites were prepared by reacting [2,4-bis(3-aminophenoxy)phenyl]diphenylphosphine oxide (3-APPO) and oxydiphthalic anhydride (ODPA) in a polar aprotic solvent in the presence of single walled carbon nanotubes and catalytic grown carbon Fibers. Thin films were subsequently cast and dried to form polyimide/carbon nanocomposites. These space environmentally durable composite Films are potentially useful in a variety of spacecraft applications such as thin film membranes on antennas, solar sails, large lightweight space optics, second-surface mirrors, thermal/optical coatings and multi-layer insulation blanket materials. The chemistry, physical and mechanical properties of the polymer nanocomposite films will be discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Watson, KA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 6 TC 12 Z9 12 U1 3 U2 7 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-91-3 J9 INT SAMPE TECH CONF PY 2001 VL 33 BP 1551 EP 1560 PG 10 WC Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BT76Y UT WOS:000173976200138 ER PT S AU Jaworske, DA Hornacek, J AF Jaworske, DA Hornacek, J BE Falcone, A Nelson, KM Albers, R Avery, WB TI Coatings for solar absorber applications in low Earth orbit SO ADVANCING AFFORDABLE MATERIALS TECHNOLOGY SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 33rd International SAMPE Technical Conference CY NOV 05-08, 2001 CL SEATTLE, WA SP Soc Advancement Mat & Process Engn, Seattle Chapter DE solar absorptance; infrared emittance; solar selective coatings ID SURFACE AB Mixed coatings containing both metal and dielectric materials can be used to tailor the optical properties of surfaces. For some space power applications, there is an interest in collecting solar energy for use in heat engines or for routing heat to remote regions of a spacecraft. The solar collector envisioned for use in these applications must have a high solar absorptance to absorb as much solar energy as possible, and a low infrared emittance to minimize energy loss. Research on solar selective coatings has progressed from coatings deposited electrochemically to coatings deposited by sputter deposition. Current research is addressing the development of cermet coatings that are durable in the low Earth orbit space environment. This paper describes past and present work on solar selective coatings, and the prospects of utilizing such coatings in low Earth orbit applications. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Jaworske, DA (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-91-3 J9 INT SAMPE TECH CONF PY 2001 VL 33 BP 1573 EP 1580 PG 8 WC Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BT76Y UT WOS:000173976200140 ER PT J AU Anderson, WK Nielsen, EJ AF Anderson, WK Nielsen, EJ TI Sensitivity analysis for Navier-Stokes equations on unstructured meshes using complex variables SO AIAA JOURNAL LA English DT Article ID TURBULENT FLOWS; GRIDS; DERIVATIVES; ALGORITHM; DESIGN AB The use of complex variables for determining sensitivity derivatives fur turbulent flows is examined. Although a step size parameter is required, the numerical derivatives are not subject to subtractive cancellation errors and, therefore, exhibit true secund-order accuracy as the step size is reduced. As a result, this technique guarantees two additional digits of accuracy each time the step size is reduced one order of magnitude. This behavior is in contrast to the use of finite differences, which suffer from inaccuracies due to subtractive cancellation errors, In addition, the complex-variable procedure is easily implemented into existing codes. C1 NASA, Langley Res Ctr, Aerodynam & Acoust Methods Branch, Fluid Mech & Acoust Div, Hampton, VA 23681 USA. Mississippi State Univ, Dept Aerosp Engn, Engn Res Ctr, Mississippi State, MS 39762 USA. Mississippi State Univ, Computat Fluid Dynam Lab, Engn Res Ctr, Mississippi State, MS 39762 USA. CNR, Fluid Mech & Acoust Div, Aerodynam & Acoust Methods Branch, Hampton, VA 23681 USA. RP Anderson, WK (reprint author), NASA, Langley Res Ctr, Aerodynam & Acoust Methods Branch, Fluid Mech & Acoust Div, Hampton, VA 23681 USA. NR 40 TC 53 Z9 53 U1 1 U2 10 PU AMER INST AERONAUTICS ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 EI 1533-385X J9 AIAA J JI AIAA J. PD JAN PY 2001 VL 39 IS 1 BP 56 EP 63 DI 10.2514/2.1270 PG 8 WC Engineering, Aerospace SC Engineering GA 390XX UT WOS:000166326000007 ER PT J AU Inger, GR Gnoffo, PA AF Inger, GR Gnoffo, PA TI Analytical and computational study of wall temperature jumps in supersonic flow SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 37th Aerospace Sciences Meeting and Exhibit CY JAN 11-14, 1999 CL RENO, NEVADA SP Amer Inst Aeronaut & Astronaut ID AERODYNAMIC CHARACTERISTICS; FLIGHT EXPERIMENT; SCHEMES; CODE AB The local viscous-inviscid interaction field generated by a wall temperature jump on a Rat plate in supersonic flow is studied in detail by the use of both a Navier-Stokes numerical code and an analytical triple-deck model. Treatment of the rapid heat transfer changes both upstream and downstream of the jump is included, Closed-form relationships for the pressure and heating variations, including upstream influence, are derived from the triple-deck theory and are found to be in good agreement with the numerical solution of the compressible Navier-Stokes equations. Such relationships not only clarify the interactive physics involved, but also are useful in preliminary design of thermal protection systems and as an insertable module to improve computational fluid dynamics code efficiency when applied to such small-scale interaction problems. Further examined is the connection between the triple-deck solution and the classical boundary-layer theory treatment of the wall temperature jump problem; the latter is shown to be similar to the far wake limit of the inner interactive behavior astride the jump. C1 Iowa State Univ Sci & Technol, Dept Aerosp Engn & Mech, Ames, IA 50011 USA. NASA, Langley Res Ctr, Aerothermodynam Branch, Aero Gas Dynam Div, Hampton, VA 23681 USA. RP Inger, GR (reprint author), Iowa State Univ Sci & Technol, Dept Aerosp Engn & Mech, Ames, IA 50011 USA. NR 19 TC 3 Z9 3 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD JAN PY 2001 VL 39 IS 1 BP 79 EP 87 DI 10.2514/2.1273 PG 9 WC Engineering, Aerospace SC Engineering GA 390XX UT WOS:000166326000010 ER PT J AU Liu, TS Guille, M Sullivan, JP AF Liu, TS Guille, M Sullivan, JP TI Accuracy of pressure-sensitive paint SO AIAA JOURNAL LA English DT Article AB Uncertainty in pressure-sensitive paint (PSP) measurement is investigated from a standpoint of system modeling. A functional relation between the imaging system output and luminescent emission from PSP is obtained based on studies of radiative energy transports in PSP and photodetector response to luminescence. This relation provides insights into physical origins of various elemental error sources and allows an estimate of the total PSP measurement uncertainty contributed by the elemental errors. The elemental errors and their sensitivity coefficients in the error propagation equation are evaluated. Useful formulas are given for the minimum pressure uncertainty that PSP can possibly achieve, as are the upper bounds of the elemental errors to meet required pressure accuracy, An instructive example of a Joukowsky airfoil in subsonic flows is given to illustrate uncertainty estimates in PSP measurements. C1 NASA, Langley Res Ctr, Model Syst Branch, Hampton, VA 23681 USA. Purdue Univ, Sch Aeronaut & Astronaut, W Lafayette, IN 47906 USA. RP Liu, TS (reprint author), NASA, Langley Res Ctr, Model Syst Branch, MS 238, Hampton, VA 23681 USA. NR 18 TC 37 Z9 39 U1 0 U2 8 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD JAN PY 2001 VL 39 IS 1 BP 103 EP 112 DI 10.2514/2.1276 PG 10 WC Engineering, Aerospace SC Engineering GA 390XX UT WOS:000166326000013 ER PT J AU Reda, DC Wilder, MC AF Reda, DC Wilder, MC TI Shear-sensitive liquid crystal coating method applied through transparent test surfaces SO AIAA JOURNAL LA English DT Article ID DISTRIBUTIONS C1 NASA, Ames Res Ctr, Space Technol Div, Moffett Field, CA 94035 USA. RP Reda, DC (reprint author), NASA, Ames Res Ctr, Space Technol Div, Moffett Field, CA 94035 USA. NR 7 TC 11 Z9 12 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD JAN PY 2001 VL 39 IS 1 BP 195 EP 197 DI 10.2514/2.1293 PG 3 WC Engineering, Aerospace SC Engineering GA 390XX UT WOS:000166326000028 ER PT S AU Dasso, S Farrugia, CJ Gratton, FT Lepping, RP Ogilvie, KW Fitzenreiter, RJ AF Dasso, S Farrugia, CJ Gratton, FT Lepping, RP Ogilvie, KW Fitzenreiter, RJ BE Lysak, RL TI Waves in the proton cyclotron frequency range in the CME observed by wind on August 7-8,1996: Theory and data SO ALFVENIC STRUCTURES: FROM THE SUN TO THE MAGNETOSPHERE SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 2 Symposium of COSPAR Scientific Commission D held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Comm Space Res ID SOLAR EJECTA; TEMPERATURE AB As first discussed by Farrugia et al. (J. Geophys. Res., 103, 6543, 1998), coronal mass ejections (CMEs) may support the excitation of electromagnetic ion cyclotron waves (EICWs). The proton plasma beta, and the electron temperature and anisotropy in the front region (similar to5 hours, translating to similar to6x10(6) km) of the CME observed by WIND on August 7-8, 1996 favor this possible excitation. Supplementing these measured parameters by other data taken from a survey of CME properties observed by the ISEE 3 spacecraft (Gosling et al., J. Geophys. Res., 92, 8519, 1987), we solve the EICW dispersion relation numerically. We find short e-folding times of EICWs, of the order of 5 min, i.e., much less than the typical evolution time of these ejecta. We suggest that high resolution data will show enhanced power in the 0.5 Hz range. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 UBA, FCEyN, CONICET, Inst Fis Plasma, RA-1033 Buenos Aires, DF, Argentina. UBA, FCEyN, Dept Phys, Buenos Aires, DF, Argentina. Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Dasso, S (reprint author), UBA, FCEyN, CONICET, Inst Fis Plasma, RA-1033 Buenos Aires, DF, Argentina. NR 16 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 28 IS 5 BP 747 EP 752 DI 10.1016/S0273-1177(01)00526-9 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT60J UT WOS:000173494100003 ER PT S AU Farrugia, CJ Vasquez, B Richardson, IG Torbert, RB Burlaga, LF Biernat, HK Muhlbachler, S Ogilvie, KW Lepping, RP Scudder, JD Berdichevsky, DE Semenov, VS Kubyshkin, IV Phan, TD Lin, RP AF Farrugia, CJ Vasquez, B Richardson, IG Torbert, RB Burlaga, LF Biernat, HK Muhlbachler, S Ogilvie, KW Lepping, RP Scudder, JD Berdichevsky, DE Semenov, VS Kubyshkin, IV Phan, TD Lin, RP BE Lysak, RL TI A reconnection layer associated with a magnetic cloud SO ALFVENIC STRUCTURES: FROM THE SUN TO THE MAGNETOSPHERE SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 2 Symposium of COSPAR Scientific Commission D held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Comm Space Res ID SOLAR-WIND; MAGNETOPAUSE; ULYSSES; FIELD; HOLES AB We examine a 3-hour long interval on December 24, 1996, containing a magnetic hole associated with an interplanetary magnetic cloud. Two sets of perturbations are observed by the Wind spacecraft at 1 AU. In the first, the field and flow rotate at constant field strength, and the plasma is accelerated to the local Alfven speed. We show this to be a rotational discontinuity. In the second, observed 25 min later, the plasma is heated and the field decreases. We show this to be a slow shock. The whole structure is in pressure balance. We interpret the observations as MHD discontinuities arriving with varying delays from a reconnection site closer to the Sun. Energetic particle observations suggest further that ejecta material is present for many hours prior to the magnetic cloud observation and separated from it by the layer. This suggests that reconnection took place between field lines of a CME of which the magnetic cloud formed a part. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Raytheon ITSS Corp, Lanham, MD USA. Univ St Petersburg, Inst Phys, St Petersburg, Russia. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP Farrugia, CJ (reprint author), Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. RI Semenov, Vladimir/A-5530-2013; Scudder, Jack/D-8417-2013; Kubyshkin, Igor/F-6243-2013 OI Richardson, Ian/0000-0002-3855-3634; Semenov, Vladimir/0000-0001-6592-056X; Scudder, Jack/0000-0001-7975-5630; Kubyshkin, Igor/0000-0001-9887-108X NR 21 TC 47 Z9 47 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 28 IS 5 BP 759 EP 764 DI 10.1016/S0273-1177(01)00529-4 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT60J UT WOS:000173494100005 ER PT S AU Tsurutani, BT Buti, B Arballo, JK Hada, T Smith, EJ Balogh, A AF Tsurutani, BT Buti, B Arballo, JK Hada, T Smith, EJ Balogh, A BE Lysak, RL TI Alfven waves, magnetic decreases, and discontinuities in interplanetary space SO ALFVENIC STRUCTURES: FROM THE SUN TO THE MAGNETOSPHERE SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 2 Symposium of COSPAR Scientific Commission D held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Comm Space Res ID ULYSSES OBSERVATIONS AB The Ulysses mission goes to the polar regions of the heliosphere and therefore is an ideal mission to study Alfven waves and discontinuities. The polar region is dominated by a high speed solar wind with embedded outwardly propagating nonlinear (\DeltaB\/B-0 similar to 1 to 2) Alfven waves. Rotational discontinuities are detected at the edges of Alfven waves and have been shown to be the phase-steepened edges of the waves. Dissipation at these phase-steepened Alfven waves has been sought in the plasma and magnetic field data, but not found. Another phenomenon detected at high latitudes is magnetic field decreases (MDs) bounded by discontinuities. One-dimensional simulation results suggest that MDs may be a product of the evolution of nonlinear Alfven waves. Published by Elsevier Science Ltd on behalf of COSPAR. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Kyushu Univ, Fukuoka 8168580, Japan. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London, England. RP Tsurutani, BT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 28 IS 5 BP 765 EP 769 DI 10.1016/S0273-1177(01)00507-5 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT60J UT WOS:000173494100006 ER PT S AU Borotto, FA Chian, ACL Gonzalez, ALC Gonzalez, WD Tsurutani, BT AF Borotto, FA Chian, ACL Gonzalez, ALC Gonzalez, WD Tsurutani, BT BE Lysak, RL TI Chaotic dynamics of large-amplitude Alfven-wave trains in the solar wind. SO ALFVENIC STRUCTURES: FROM THE SUN TO THE MAGNETOSPHERE SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT D0 2 Symposium of COSPAR Scientific Commission D held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Comm Space Res ID TURBULENCE; ATTRACTORS; PLASMAS; INTERMITTENCY; FLUCTUATIONS; ULYSSES; DRIVEN AB The chaotic dynamics of a driven-dissipative Alfven system is studied by analyzing the stationary solutions of the derivative nonlinear Schrodinger equation. We demonstrate that there are two types of Alfven intermittency. In the Pomeau-Manneville intermittency, the time series of magnetic field fluctuations switches intermittently between nearly periodic and chaotic states; whereas, in the crisis-induced intermittency, the time series of magnetic field fluctuations switches intermittently between weakly and strongly chaotic states. These nonlinear dynamic phenomena can improve our understanding of Alfvenic chaos and turbulence observed in the solar wind. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Concepcion, Dept Fis, Concepcion, Chile. INPE, Natl Inst Space Res, BR-12201970 Sao Jose Dos Campos, SP, Brazil. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Borotto, FA (reprint author), Univ Concepcion, Dept Fis, Concepcion, Chile. NR 22 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES-SERIES PY 2001 VL 28 IS 5 BP 771 EP 774 DI 10.1016/S0273-1177(01)00524-5 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT60J UT WOS:000173494100007 ER PT B AU Nunes, AC AF Nunes, AC BE Das, SK Kaufman, JG Lienert, TJ TI Wiping metal transfer in Friction Stir Welding SO ALUMINUM 2001: PROCEEDINGS OF THE TMS 2001 ANNUAL MEETING ALUMINUM AUTOMOTIVE AND JOINING SYMPOSIA LA English DT Proceedings Paper CT Symposium on Automotive Aluminum 2001/Aluminum Joining Including Friction Stir Welding held at the 2001 TMS Annual Meeting CY FEB 12-14, 2001 CL NEW ORLEANS, LA SP Aluminum Assoc, Minerals, Met & Mat Soc AB In Friction Stir Welding (FSW) a rotating pin-tool inserted into a weld seam literally stirs the edges of the seam together. The superposition of a rapidly rotating cylinder, a slowly rotating ring vortex, and a uniform translational flow generates a "wiping" flow that appears to model the plastic flow around the pin-tool. The wiping model is described and used to explain the results of a number of tracer experiments (traversed slab, line of shot, traversed wires). The wiping process model is compared to the metal cutting process and shown to have much in common, including very high strain rates. The model comprises a starting point for the rational design of the FSW pin-tool. C1 NASA, George C Marshall Space Flight Ctr, Mat Proc & Mfg Dept, ED33, Huntsville, AL 35812 USA. RP Nunes, AC (reprint author), NASA, George C Marshall Space Flight Ctr, Mat Proc & Mfg Dept, ED33, Huntsville, AL 35812 USA. NR 8 TC 6 Z9 6 U1 3 U2 8 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-509-3 PY 2001 BP 235 EP 248 PG 14 WC Metallurgy & Metallurgical Engineering; Transportation Science & Technology SC Metallurgy & Metallurgical Engineering; Transportation GA BT17X UT WOS:000172165700020 ER PT J AU Tobin, BW Leeper-Woodford, SK Hashemi, BB Smith, SM Sams, CF AF Tobin, BW Leeper-Woodford, SK Hashemi, BB Smith, SM Sams, CF TI Altered TNF-alpha, glucose, insulin, and amino acids in islets of Langerhans cultured in a microgravity model system SO AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM LA English DT Article DE tumor necrosis factor-alpha; cytokines; diabetes; amino acids ID NECROSIS-FACTOR-ALPHA; DEPENDENT DIABETES-MELLITUS; PANCREATIC-ISLETS; GENE-EXPRESSION; SPACEFLIGHT; TRANSPLANTATION; RESISTANCE; SECRETION; SPACE; GLUTAMINE AB The present studies were designed to determine effects of a microgravity model system upon lipopolysaccharide (LPS)-stimulated tumor necrosis factor-alpha (TNF-alpha) activity and indexes of insulin and fuel homeostasis of pancreatic islets of Langerhans. Islets (1,726 +/- 117, 150 islet equivalent units) from Wistar-Furth rats were treated as 1) high aspect ratio vessel (HARV) cell culture, 2) HARV plus LPS, 3) static culture, and 4) static culture plus LPS. TNF-alpha (L929 cytotoxicity assay) was significantly increased in LPS-induced HARV and static cultures; yet the increase was more pronounced in the static culture group (P < 0.05). A decrease in insulin concentration was demonstrated in the LPS-stimulated HARV culture (P < 0.05). We observed a greater glucose concentration and increased disappearance of arginine in islets cultured in HARVs. Although nitrogenous compound analysis indicated a ubiquitous reliance on glutamine in all experimental groups, arginine was converted to ornithine at a twofold greater rate in the islets cultured in the HARV microgravity model system (P < 0.05). These studies demonstrate alterations in LPS-induced TNF- production of pancreatic islets of Langerhans, favoring a lesser TNF activity in the HARV. These alterations in fuel homeostasis may be promulgated by gravity-averaged cell culture methods or by three-dimensional cell assembly. C1 Mercer Univ, Sch Med, Program Nutr & Biochem, Diabet Res Lab, Macon, GA 31207 USA. Mercer Univ, Sch Med, Div Basic Med Sci, Program Physiol, Macon, GA 31207 USA. Natl Space Biomed Res Inst, Houston, TX 77030 USA. NASA, Nutr Biochem Lab, Life Sci Res Labs, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NASA, Lab Human Immune Funct & Signal Transduct, Life Sci Res Labs, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Tobin, BW (reprint author), Mercer Univ, Sch Med, Program Nutr & Biochem, Diabet Res Lab, 1550 Coll St, Macon, GA 31207 USA. NR 42 TC 11 Z9 12 U1 0 U2 3 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0193-1849 J9 AM J PHYSIOL-ENDOC M JI Am. J. Physiol.-Endocrinol. Metab. PD JAN PY 2001 VL 280 IS 1 BP E92 EP E102 PG 11 WC Endocrinology & Metabolism; Physiology SC Endocrinology & Metabolism; Physiology GA 383WZ UT WOS:000165908800012 PM 11120663 ER PT J AU Dieters, S AF Dieters, S TI Requiem for a great observatory SO AMERICAN SCIENTIST LA English DT Article C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Dieters, S (reprint author), Arizona Western Coll, Div Sci & Math, Box 929,Main Campus, Yuma, AZ 85366 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SIGMA XI-SCI RES SOC PI RES TRIANGLE PK PA PO BOX 13975, RES TRIANGLE PK, NC 27709 USA SN 0003-0996 J9 AM SCI JI Am. Scientist PD JAN-FEB PY 2001 VL 89 IS 1 BP 8 EP 9 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 383ED UT WOS:000165869400010 ER PT J AU Fuerstenau, SD Benner, WH Thomas, JJ Brugidou, C Bothner, B Siuzdak, G AF Fuerstenau, SD Benner, WH Thomas, JJ Brugidou, C Bothner, B Siuzdak, G TI Mass spectrometry of an intact virus SO ANGEWANDTE CHEMIE-INTERNATIONAL EDITION LA English DT Article ID ELECTROSPRAY IONS; CHARGE; COMPLEXES C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Scripps Res Inst, Ctr Mass Spectrometry, La Jolla, CA 92037 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Benner, WH (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, MS 70A-3363,1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 24 TC 69 Z9 70 U1 1 U2 24 PU WILEY-V C H VERLAG GMBH PI BERLIN PA PO BOX 10 11 61, D-69451 BERLIN, GERMANY SN 1433-7851 J9 ANGEW CHEM INT EDIT JI Angew. Chem.-Int. Edit. PY 2001 VL 40 IS 3 BP 542 EP 544 PG 3 WC Chemistry, Multidisciplinary SC Chemistry GA 400XZ UT WOS:000166899100006 ER PT J AU Amodei, M Pawson, S Scaife, AA Langematz, U Lahoz, W Li, DM Simon, P AF Amodei, M Pawson, S Scaife, AA Langematz, U Lahoz, W Li, DM Simon, P TI The SAO and Kelvin waves in the EuroGRIPS GCMS and the UK Met. Office analyses SO ANNALES GEOPHYSICAE LA English DT Article DE meteorology and atmospheric dynamics (middle; atmosphere dynamics; tropical meterology; waves and tides) ID GENERAL-CIRCULATION MODEL; QUASI-BIENNIAL OSCILLATION; STRATOSPHERE-MESOSPHERE GCM; TROPICAL MIDDLE ATMOSPHERE; EQUATORIAL LOWER STRATOSPHERE; QBO-LIKE OSCILLATION; SEMIANNUAL OSCILLATION; SIMPLE PARAMETERIZATION; CUMULUS CONVECTION; UNIFIED MODEL AB We compare the tropical oscillations and planetary scale Kelvin waves in four troposphere-stratosphere climate models and the assimilated dataset produced by the United Kingdom Meteorological Office (UKMO). The comparison has been made in the GRIPS framework "GCM-Reality Intercomparison Project for SPARC", where SPARC is Stratospheric Processes and their Role in Climate, a project of the World Climate Research Program. The four models evaluated are European members of GRIPS: the UKMO Unified Model (UM), the model of the Free University in Berlin (FUB-GCM), the ARPEGE-climat model of the French National Centre for Meteorological Research (CNRM), and the Extended UGAMP GCM (EUGCM) of the Centre for Global Atmospheric Modelling (CGAM). The integrations were performed with different, but annually periodic external conditions (e.g., sea-surface temperature, sea ice, and incoming solar radiation). The structure of the tropical winds and the strengths of the Kelvin waves are examined. In the analyses where the SAO (Semi-Annual Oscillation) and the QBO (Quasi-Biennal Oscillation) are reasonably well captured, the amplitude of these analysed Kelvin waves is close to that observed in independent data from UARS (Upper Atmosphere Research Satellite). In agreement with observations, the Kelvin waves generated in the models propagate into the middle atmosphere as wave packets, consistent with a convective forcing origin. In three of the models, slow Kelvin waves propagate too high and their amplitudes are overestimated in the upper stratosphere and in the mesosphere, the exception is the UM which has weaker waves. None of the modelled waves are sufficient to force realistic eastward phases of the QBO or SAG. Although the SAO is represented by all models, only two of them are able to generate westerlies between 10 hPa and 50 hPa. The importance of the role played in the SAO by unresolved gravity waves is emphasized. Although it exhibits some unrealistic features, the EUGCM, which includes a parametrization of gravity waves with a non-zero phase speed, is able to simulate clear easterly to westerly transitions as well as westerlies with downward propagation. Thermal damping is also important for the westerly forcing in the stratosphere. C1 Meteo France, CNRM, Toulouse, France. NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Seabrook, MD USA. Meteorol Off, Bracknell RB12 2SZ, Berks, England. Free Univ Berlin, D-1000 Berlin, Germany. Univ Reading, Ctr Global Atmospher Modelling, Reading RG6 2AH, Berks, England. RP Amodei, M (reprint author), Meteo France, CNRM, Toulouse, France. EM marielle.amodei@meteo.fr RI Pawson, Steven/I-1865-2014 OI Pawson, Steven/0000-0003-0200-717X NR 56 TC 11 Z9 11 U1 0 U2 3 PU COPERNICUS GESELLSCHAFT MBH PI GOTTINGEN PA BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY SN 0992-7689 EI 1432-0576 J9 ANN GEOPHYS-GERMANY JI Ann. Geophys. PD JAN PY 2001 VL 19 IS 1 BP 99 EP 114 PG 16 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 453DC UT WOS:000169900400010 ER PT J AU Zerefos, C Balis, D Tzortziou, M Bais, A Tourpali, K Meleti, C Bernhard, G Herman, J AF Zerefos, C Balis, D Tzortziou, M Bais, A Tourpali, K Meleti, C Bernhard, G Herman, J TI A note on the interannual variations of UV-B erythemal doses and solar irradiance from ground-based and satellite observations SO ANNALES GEOPHYSICAE LA English DT Article DE atmospheric composition and structure (geochemical cycles; transmission and scattering of radiation) ID QUASI-BIENNIAL OSCILLATION; TOTAL OZONE; ULTRAVIOLET-RADIATION; SURFACE; CLOUDS AB This study examines three UV-B data sets: groundbased long-term spectral records at Thessaloniki, Greece (40.5 degrees N, 22.9 degrees E) and San Diego, California, USA (33.7 degrees N, 117.2 degrees W) as well as a global data set of daily erythemal dose obtained from the Total Ozone Mapping Spectrometer (TOMS) onboard the Nimbus-7 satellite. Both ground-based stations have long enough records of spectral UV-B measurements to allow independent time series analyses. For 63 degrees solar zenith angle (SZA) and clear sky conditions the quasi biennial oscillation (QBO) effect in solar irradiance at 305nm E-305 is about 32% of the annual cycle for both San Diego and Thessaloniki. The effect slightly increases with cloud cover of up to 4/8, and decreases thereafter for cloud cover greater than 4/8. The data reveal that cloudiness cannot offset interannual signals in UV-B records. The observations at San Diego provide an independent confirmation of the widespread nature of the QBO in UV-B, which about coincides in amplitude at the two station studies, both located in the latitude zone 30 degrees -40 degrees N. The peak-to-peak amplitude of the QBO in erythemal dose derived from TOMS/Nimbus7 data is 6.5% at Thessaloniki. This is similar to the values calculated from ground-based measurements from this station. Based on satellite data, we find that the amplitude of the QBO in the erythemal dose is almost 40% of the amplitude of the annual cycle only in the tropics. The ratio of the amplitudes of the QBO over the annual cycle in erythemal dose decreases towards the extratropics, becoming less than 5% over middle latitudes. C1 Aristotelian Univ Salonika, Lab Atmospher Phys, GR-54006 Salonika, Greece. Biospher Instruments Inc, San Diego, CA USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Zerefos, C (reprint author), Aristotelian Univ Salonika, Lab Atmospher Phys, GR-54006 Salonika, Greece. RI Bais, Alkiviadis/D-2230-2009; Tourpali, Kleareti/M-5269-2014; OI Bais, Alkiviadis/0000-0003-3899-2001; Herman, Jay/0000-0002-9146-1632; Balis, Dimitris/0000-0003-1161-7746 NR 26 TC 15 Z9 15 U1 0 U2 1 PU EUROPEAN GEOPHYSICAL SOCIETY PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 0992-7689 J9 ANN GEOPHYS JI Ann. Geophys. PD JAN PY 2001 VL 19 IS 1 BP 115 EP 120 PG 6 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 453DC UT WOS:000169900400011 ER PT S AU Drinkwater, MR Liu, X Harms, S AF Drinkwater, MR Liu, X Harms, S BE Jeffries, MO Eicken, H TI Combined satellite- and ULS-derived sea-ice flux in the Weddell Sea, Antarctica SO ANNALS OF GLACIOLOGY, VOL 33 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International-Glaciological-Society Symposium on Sea Ice and Its Interactions with the Ocean, Atmosphere and Biosphere CY JUN 19-23, 2000 CL UNIV ALASKA FAIRBANKS, FAIRBANKS, ALASKA SP Arct Res Consortium US, Frontier Res Syst Global Change, US Natl Aeronaut & Space Adm, US Natl Sci Fdn, US Off Naval Res, Amer Geophys Union, Int Arct Sci Comm, Int Assoc Phys Sci Ocean, Sea Ice Commiss, Int Commiss Snow & Ice, Japanese Soc Snow & Ice, Sci Comm Antarct Res HO UNIV ALASKA FAIRBANKS ID THICKNESS DISTRIBUTION; MOTION; OCEAN; MODEL AB Several,;ears of daily micro-wave satellite ice drift are combined with moored upward-looking sonar (ULS) ice drafts into an ice-volume flux record at points along a flux gate across the Weddell Sea, Antarctica. Monthly ice transport varies at the mooring locations From a maximum export of 0.4 m(3) s(-1) near Joinville Island to -0.4 m(3) s(-1) imported along the Fimbul and Riiser-Larsen ice-shelf margins. Winter peaks are observed at each end of the flux gate, where high concentrations of deformed ice are advected in and out of the basin along the coastline. The central gyre, in contrast, exhibits negligible seasonality and much smaller volume transports, During the period of overlapping ULS operation, the mean monthly integrated ice export west of the gyre center is 59 x 10 m(3) s(-1) and the import in the East Wind Drift is -17 x 10(3) m(3) s(-1) ULS data are compared with ERS satellite observation of radar backscatter to obtain an empirical relationship between ice thickness and the rate of change of backscatter with incidence angle. Resulting proxy ice-thickness data are combined with Special Sensor Microwave/Imager-derived ice velocities to obtain seasonally varying estimates of net ice-volume flux for the period 1992-98. Significant inter-annual variability is observed in ice-volume flux expressed as fresh-water transport. A maximum annual mean of 0.054 Sv is observed in 1992, with a minimum of 0.015 Sv in 1996. A 6 year mean transport of 0.032 Sv is observed. Maximum seasonal ice export occurs injury 1992, with a minimum in November 1996. The 10 year mean area flux is 30 x 10(3) m(2) s(-1). Inter-annual variations in net volume flux closely follow variations in area flux, with Summer minima in 1990/91 and 1996/97. Maximum area transport occurs in 1991, and although this predates the ERS-1 scatterometer data, ice-thickness estimates by Harms and others confirm 1991 as a decadal peak in net integrated fresh-water transport. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Alfred Wegener Inst Polar & Marine Res, D-27515 Bremerhaven, Germany. RP Drinkwater, MR (reprint author), European Space Agcy, Estec, Keplerlaan 1,POB 299, NL-2200 AG Noordwijk, Netherlands. RI Drinkwater, Mark/C-2478-2011 OI Drinkwater, Mark/0000-0002-9250-3806 NR 33 TC 11 Z9 13 U1 0 U2 2 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-28-8 J9 ANN GLACIOL PY 2001 VL 33 BP 125 EP 132 DI 10.3189/172756401781818446 PG 8 WC Geosciences, Multidisciplinary SC Geology GA BT59X UT WOS:000173446300019 ER PT S AU Zhao, YH Liu, AK AF Zhao, YH Liu, AK BE Jeffries, MO Eicken, H TI Principal-component analysis of sea-ice motion from satellite data SO ANNALS OF GLACIOLOGY, VOL 33 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International-Glaciological-Society Symposium on Sea Ice and Its Interactions with the Ocean, Atmosphere and Biosphere CY JUN 19-23, 2000 CL UNIV ALASKA FAIRBANKS, FAIRBANKS, ALASKA SP Arct Res Consortium US, Frontier Res Syst Global Change, US Natl Aeronaut & Space Adm, US Natl Sci Fdn, US Off Naval Res, Amer Geophys Union, Int Arct Sci Comm, Int Assoc Phys Sci Ocean, Sea Ice Commiss, Int Commiss Snow & Ice, Japanese Soc Snow & Ice, Sci Comm Antarct Res HO UNIV ALASKA FAIRBANKS ID WAVELET ANALYSIS; IMAGERY; DRIFT; SAR AB The two-dimensional wavelet transform is a highly efficient band-pass filter, which can be used to track features in satellite images from sequential paths. Wavelet analysis of NASA scatterometer and Special Sensor Microwave/Imager data has been used to obtain daily sea-ice drift information for the Arctic region. Comparison with ice motion derived from ocean buoys shows good quantitive agreement. Furthermore, the scatterometer results definitely complement passive-microwave radiometer results when there are cloud or surface effects. This outcome allows three sets of sea-ice-drift daily results from scatterometer, radiometer and buoy data to be merged as a composite map by dam-fusion techniques. Based on the composite maps, the ice-flow streamlines are highly correlated with surface air-pressure contours. In order to quantify the wind effects on ice motion, empirical orthogonal functions are used in the principal-component analysis to isolate generalized patterns inherent in 6 months (fall/winter) of daily sea-ice motion data. It is found that 30% of sea-ice motion is highly correlated with 50% of the pressure field in modes 1 and 2. For the higher modes, sea-ice motion is also affected by ocean Current, bathymetry and coastal boundary and therefore is not highly correlated with the wind field. C1 NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. RP Zhao, YH (reprint author), NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Code 971, Greenbelt, MD 20771 USA. NR 16 TC 2 Z9 2 U1 0 U2 1 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-28-8 J9 ANN GLACIOL PY 2001 VL 33 BP 133 EP 138 DI 10.3189/172756401781818798 PG 6 WC Geosciences, Multidisciplinary SC Geology GA BT59X UT WOS:000173446300020 ER PT S AU Ukita, J Martinson, DG AF Ukita, J Martinson, DG BE Jeffries, MO Eicken, H TI An efficient adjustable-layering thermodynamic sea-ice model formulation for high-frequency forcing SO ANNALS OF GLACIOLOGY, VOL 33 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International-Glaciological-Society Symposium on Sea Ice and Its Interactions with the Ocean, Atmosphere and Biosphere CY JUN 19-23, 2000 CL UNIV ALASKA FAIRBANKS, FAIRBANKS, ALASKA SP Arct Res Consortium US, Frontier Res Syst Global Change, US Natl Aeronaut & Space Adm, US Natl Sci Fdn, US Off Naval Res, Amer Geophys Union, Int Arct Sci Comm, Int Assoc Phys Sci Ocean, Sea Ice Commiss, Int Commiss Snow & Ice, Japanese Soc Snow & Ice, Sci Comm Antarct Res HO UNIV ALASKA FAIRBANKS ID BELLINGSHAUSEN; ANTARCTICA; AMUNDSEN; EXCHANGE AB Recent observations suggest that high-frequency forcing events have profound influence oil the air-sea-ice interactions in the polar region. Studying these events with sea-ice models requires close examination of the model sensitivity that may arise from the high-frequency variability of the forcing. We show that the maximum layer thickness is dictated by the time-scale of the forcing variability and that the computation of the surface temperature develops enhanced sensitivity at high-frequency forcing. We resolve these constrains by developing all "adjustable-layering" thermodynamic formulation for ice and snow that re-computes the number of layers required each time-step to satisfy this maximum thickness, which preserves the total enthalpy and general internal thermal gradients. The conservation equations form a tri-diagonal system ideal for a Fast and efficient implicit solution. Furthermore, we resolve the issue of the high sensitivity of the surface flux balance by solving the linearized version of the flux boundary condition simultaneously with the overall conservation system. In this paper we develop the analyses specifying the model requirements, describe the model system and test its algorithmic implementation. C1 Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. RP Ukita, J (reprint author), NASA, Goddard Space Flight Ctr, UMBC, Code 971, Greenbelt, MD 20771 USA. NR 22 TC 1 Z9 1 U1 0 U2 2 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-28-8 J9 ANN GLACIOL PY 2001 VL 33 BP 253 EP 260 DI 10.3189/172756401781818194 PG 8 WC Geosciences, Multidisciplinary SC Geology GA BT59X UT WOS:000173446300040 ER PT S AU Ackley, SF Geiger, CA King, JC Hunke, EC Comiso, J AF Ackley, SF Geiger, CA King, JC Hunke, EC Comiso, J BE Jeffries, MO Eicken, H TI The Ronne polynya of 1997/98: observations of air-ice-ocean interaction SO ANNALS OF GLACIOLOGY, VOL 33 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International-Glaciological-Society Symposium on Sea Ice and Its Interactions with the Ocean, Atmosphere and Biosphere CY JUN 19-23, 2000 CL UNIV ALASKA FAIRBANKS, FAIRBANKS, ALASKA SP Arct Res Consortium US, Frontier Res Syst Global Change, US Natl Aeronaut & Space Adm, US Natl Sci Fdn, US Off Naval Res, Amer Geophys Union, Int Arct Sci Comm, Int Assoc Phys Sci Ocean, Sea Ice Commiss, Int Commiss Snow & Ice, Japanese Soc Snow & Ice, Sci Comm Antarct Res HO UNIV ALASKA FAIRBANKS ID BOTTOM WATER FORMATION; WEDDELL SEA AB The Ronne polynya formed in the Weddell Sea, Antarctica, during the period November 1997-February 1998 to an extent not seen previously in the 25 years of all-weather satellite observations. The vessel HMS Endurance traversed the polynya region and took sea-ice, physical oceanographic and meteorological measurements during January and early February 1998. These observations, together with satellite imagery and weather records, were analyzed to determine the causes of the anomalous condition observed and to provide comparisons for numerical modeling experiments. The polynya area, analyzed from satellite imagery, showed a linear, nearly constant, increase with time from mid-November 1997 through February 1998. It had a maximum open-water area of 3 X 10(5) km(2) and extended 500 km north of the Ronne Ice Shelf (at 76degrees S) to 70degrees S. The ice and snow structure of floes at (lie northern edge of the polynya showed the ice there had formed in the previous mid- to late winter October 1997 or earlier) and had been advected there either from the eastern Weddell Sea or from the front of the Ronne Ice Shelf. Analyses of the wind fields showed anomalous spring -summer wind fields in the polynya year, with a strong southerly to southwesterly component compared to the mean easterly winds typical of summer conditions. These southerly wind conditions, ill both magnitude and direction, therefore account for the drift of ice northward. The predominant summer easterly winds usually fill the southern Weddell Sea with ice from the east, and the high-albedo surfaces reflect (lie solar radiation, preventing warming of the surface ocean waters and consequent sea-ice melt. Instead, high incident solar radiation From November 1997 to February 1998 was absorbed by (lie open water, rather than being reflected, thereby both melting ice and preventing ice formation, and thereby sustaining the polynya. We conclude that open-water-albedo feedback is necessary to allow the observed polynya formation, since similar drift conditions prevail in winter (arising from southerly winds also) and usually, result in extensive new ice formation in front of the Ronne Ice Shelf. The strong southerly winds therefore have quite opposing seasonal effects, leading to high ice production ill winter as usually found, and extensive open water if they occur in spring and Summer, as seen in this atypical event in 1997/98. In this case, the atypical southerly winds may be associated with all El Nino-Southern Oscillation (ENSO) -induced atmospheric circulation pattern. C1 Clarkson Univ, Dept Civil & Environm Engn, Potsdam, NY 13699 USA. Univ Delaware, Dept Geog, Ctr Climat Res, Newark, DE 19716 USA. British Antarctic Survey, NERC, Cambridge CB3 0ET, England. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Ackley, SF (reprint author), Clarkson Univ, Dept Civil & Environm Engn, Potsdam, NY 13699 USA. NR 10 TC 25 Z9 25 U1 0 U2 3 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-28-8 J9 ANN GLACIOL PY 2001 VL 33 BP 425 EP 429 DI 10.3189/172756401781818725 PG 5 WC Geosciences, Multidisciplinary SC Geology GA BT59X UT WOS:000173446300067 ER PT S AU Comiso, JC AF Comiso, JC BE Jeffries, MO Eicken, H TI Satellite-observed variability and trend in sea-ice extent, surface temperature, albedo and clouds in the Arctic SO ANNALS OF GLACIOLOGY, VOL 33 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International-Glaciological-Society Symposium on Sea Ice and Its Interactions with the Ocean, Atmosphere and Biosphere CY JUN 19-23, 2000 CL UNIV ALASKA FAIRBANKS, FAIRBANKS, ALASKA SP Arct Res Consortium US, Frontier Res Syst Global Change, US Natl Aeronaut & Space Adm, US Natl Sci Fdn, US Off Naval Res, Amer Geophys Union, Int Arct Sci Comm, Int Assoc Phys Sci Ocean, Sea Ice Commiss, Int Commiss Snow & Ice, Japanese Soc Snow & Ice, Sci Comm Antarct Res HO UNIV ALASKA FAIRBANKS ID AIR-TEMPERATURE; COVER; SNOW AB Recent observations of a decreasing ice extent and a possible thinning of the ice cover in the Arctic make it imperative that detailed studies of the current Arctic environment are made, especially since the region is known to be highly sensitive to a potential change in climate. A continuous dataset of microwave, thermal infrared and visible satellite data has been analyzed for the first time to concurrently study, in spatial detail the variability of the sea-ice cover, surface temperature, albedo and cloud statistics in the region from 1987 to 1998. Large warming anomalies during the last four years (i.e. 1995-98) are indeed apparent and spatially more extensive than previous years. The largest surface temperature anomaly occurred in 1998, but this was confined mainly to the western Arctic and the North American continent, while cooling occurred in other areas. The albedo anomalies show good coherence with the sea-ice concentration anomalies except in the central region, where periodic changes in albedo are observed, indicative of inter-annual changes in duration and areal extent of melt ponding and snow-free ice cover. The cloud-cover anomalies are more difficult to interpret, but are shown to be well correlated with the expected warming effects of clouds on the sea-ice surface. The results from trend analyses of the data are consistent with a general warming trend and an ice-cover retreat that appear to be even larger during the last dozen years than those previously reported. C1 NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. RP Comiso, JC (reprint author), NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Code 971, Greenbelt, MD 20771 USA. NR 21 TC 22 Z9 23 U1 3 U2 9 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-28-8 J9 ANN GLACIOL PY 2001 VL 33 BP 457 EP 473 DI 10.3189/172756401781818617 PG 17 WC Geosciences, Multidisciplinary SC Geology GA BT59X UT WOS:000173446300072 ER PT S AU Nazarenko, L Hansen, J Tausnev, N Ruedy, R AF Nazarenko, L Hansen, J Tausnev, N Ruedy, R BE Jeffries, MO Eicken, H TI Response of the Northern Hemisphere sea ice to greenhouse forcing in a global climate model SO ANNALS OF GLACIOLOGY, VOL 33 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International-Glaciological-Society Symposium on Sea Ice and Its Interactions with the Ocean, Atmosphere and Biosphere CY JUN 19-23, 2000 CL UNIV ALASKA FAIRBANKS, FAIRBANKS, ALASKA SP Arct Res Consortium US, Frontier Res Syst Global Change, US Natl Aeronaut & Space Adm, US Natl Sci Fdn, US Off Naval Res, Amer Geophys Union, Int Arct Sci Comm, Int Assoc Phys Sci Ocean, Sea Ice Commiss, Int Commiss Snow & Ice, Japanese Soc Snow & Ice, Sci Comm Antarct Res HO UNIV ALASKA FAIRBANKS ID LAYER OCEAN MODEL; POLAR CLIMATE; CO2; SENSITIVITY; VARIABILITY; COVER; ATMOSPHERE; SIMULATIONS; TRENDS AB The Q-flux Goddard Institute of Space Studies (GISS) global climate model, in which an atmospheric general circulation model is coupled to a mixed-layer ocean with specified horizontal heat transports, is used to simulate the transient and equilibrium climate response to a gradual increase of carbon dioxide (1% per year increase of CO2 to doubled CO2). The results indicate that the current GISS model has a high sensitivity with a global annual warming of about 4degreesC for doubled CO2. Enhanced warming is found at higher latitudes near sea-ice margins due to retreat of sea ice in the greenhouse experiment. Surface warming is larger in winter than in summer, in part because of the reductions in ice cover and thickness that insulate the winter atmosphere from the ocean. The annual mean reduction of sea-ice cover due to doubled CO2 is about 30% for the Northern Hemisphere. The CO2 experiment has a 70% reduction of sea-ice area and 55% thinning of ice in August in the Northern Hemisphere. Noticeable reduction of sea-ice cover has been found in both historical records and satellite observations. The largest reduction of simulated sea-ice extent occurs in summer, consistent with observations. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Ctr Climate Syst Res, New York, NY 10025 USA. Rutgers State Univ, New York, NY 10025 USA. RP Nazarenko, L (reprint author), NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NR 34 TC 1 Z9 1 U1 1 U2 2 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-28-8 J9 ANN GLACIOL PY 2001 VL 33 BP 513 EP 520 DI 10.3189/172756401781818897 PG 8 WC Geosciences, Multidisciplinary SC Geology GA BT59X UT WOS:000173446300078 ER PT S AU Nazarenko, L Tausnev, N AF Nazarenko, L Tausnev, N BE Jeffries, MO Eicken, H TI Modeling of the Beaufort ice-ocean climatology change SO ANNALS OF GLACIOLOGY, VOL 33 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International-Glaciological-Society Symposium on Sea Ice and Its Interactions with the Ocean, Atmosphere and Biosphere CY JUN 19-23, 2000 CL UNIV ALASKA FAIRBANKS, FAIRBANKS, ALASKA SP Arct Res Consortium US, Frontier Res Syst Global Change, US Natl Aeronaut & Space Adm, US Natl Sci Fdn, US Off Naval Res, Amer Geophys Union, Int Arct Sci Comm, Int Assoc Phys Sci Ocean, Sea Ice Commiss, Int Commiss Snow & Ice, Japanese Soc Snow & Ice, Sci Comm Antarct Res HO UNIV ALASKA FAIRBANKS ID SEA-ICE; TOPOGRAPHIC STRESS; ARCTIC OCEAN; SIMULATIONS; COVER; CIRCULATION; VARIABILITY; EDDY AB A coupled ice-ocean model is used to study the sensitivity of the Beaufort climatology to representation of sub-grid-scale eddies; to hypothetically not present and double Mackenzie River discharge. and to approximate climate warming specified through a surface air-temperature increase of 3degreesC. The eddy effect is considered in two ways: as eddy interaction with sea-floor topography yielding driving force ("neptune" parameterization) and as eddy diffusion and viscosity. The model with neptune parameterization reproduces surface layer circulation, as well as the bathymetrically steered Beaufort Under-current, while the model with usual damping does not simulate the Beaufort Undercurrent. The absence of the strong boundary Beaufort Undercurrent affects the thermohaline structure of the Beaufort Sea which becomes less consistent with observational data. The increase of the Mackenzie River discharge causes more northward transport of sea-ice, resulting in sea-ice thinning in Mackenzie Bay, while the absence of the Mackenzie River discharge induces southward sea-ice drift and sea-ice thickening in Mackenzie Bay. The sensitivity study of surface air-temperature warming shows a shrinkage of sea ice by 6% in area and 15% in volume, causing the freshening and warming of the surface ocean layer. The sensitivity studies of river discharge and surface air temperature use the neptune parameterization. C1 Columbia Univ, NASA, Goddard Inst Space Studies, Ctr Climate Syst Res, New York, NY 10025 USA. Rutgers State Univ, NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Nazarenko, L (reprint author), Columbia Univ, NASA, Goddard Inst Space Studies, Ctr Climate Syst Res, New York, NY 10025 USA. NR 37 TC 3 Z9 3 U1 0 U2 2 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-28-8 J9 ANN GLACIOL PY 2001 VL 33 BP 560 EP 566 DI 10.3189/172756401781818491 PG 7 WC Geosciences, Multidisciplinary SC Geology GA BT59X UT WOS:000173446300086 ER PT J AU Morris, R Khatib, L AF Morris, R Khatib, L TI General temporal knowledge for planning and data mining SO ANNALS OF MATHEMATICS AND ARTIFICIAL INTELLIGENCE LA English DT Article ID ABSTRACTION; AI AB We consider the architecture of systems that combine temporal planning and plan execution and introduce a layer of temporal reasoning that potentially improves both the communication between humans and such systems, and the performance of the temporal planner itself. In particular, this additional layer simultaneously supports more flexibility in specifying and maintaining temporal constraints on plans within an uncertain and changing execution environment, and the ability to understand and trace the progress of plan execution. It is shown how a representation based on single set of abstractions of temporal information can be used to characterize the reasoning underlying plan generation and execution interpretation. The complexity of such reasoning is discussed. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Kestrel Technol, NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Morris, R (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 24 TC 8 Z9 8 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 1012-2443 J9 ANN MATH ARTIF INTEL JI Ann. Math. Artif. Intell. PY 2001 VL 33 IS 1 BP 1 EP 19 DI 10.1023/A:1012361914091 PG 19 WC Computer Science, Artificial Intelligence; Mathematics, Applied SC Computer Science; Mathematics GA 481RF UT WOS:000171532900001 ER PT S AU Zampino, EJ AF Zampino, EJ GP IEEE TI Application of fault-tree analysis to troubleshooting the NASA GRC icing research tunnel SO ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM, 2001 PROCEEDINGS SE PROCEEDINGS : ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT Annual Reliability and Maintainaability Symposium CY JAN 22-25, 2001 CL PHILADELPHIA, PENNSYLVANIA SP IEEE, SAE, IIE, SLE, EST, Soc Reliability Engineers DE corrective action; failure; failure cause determination; faults; functions; reliability improvement; team approach; training AB In 1997, the NASA Glenn Research Center in Cleveland Ohio conducted an extensive troubleshooting effort on its icing Research Wind Tunnel (known as the IRT). This effort utilized fault tree analysis as an analytical troubleshooting tool in order to "attack" a serious non-repeatability problem with IRT icing cloud parameters. A team of knowledgeable managers, engineers, and technicians was formed to conduct the analysis. The construction of the IRT fault tree created a "picture" of the causal structure of potential faults that could contribute to the existence of a non-repeatability problem. The analysis team investigated many problem areas that were indicated by the fault tree. The Fault Tree Analysis was an important aid in the troubleshooting effort which pulled in organizations needed to investigate the problem and caused a number of simultaneous corrective actions to occur. These actions were critical in restoring the repeatability of the icing cloud parameters even though no single root cause of the problem could be identified. In addition, the analysis team found 9 system level considerations which were brought forward to improve tunnel operations. The possibility of implementing the recommendations was investigated by the IRT staff. It was found that many of the recommendations had already been a matter of practice for quite a long time, but others were not and were selected for implementation. We learned that the effectiveness of the analysis was greatly enhanced by a team approach, and by a critical team review of all fault tree sections constructed. Personnel investigated the possibility that certain fault events could exist even when it appeared that the likelihood of an event was small. Intermediate events or potential primary faults were not removed from the fault tree unless sufficient evidence was presented to do so. The IRT management also realized that the fault tree analysis report provided a baseline and history for the investigation of this non-repeatability problem. If it was to re-occur, NASA Glenn Research Center would have an analytical record of the procedure followed to solve the problem and would not have to re-start from "ground zero." It was learned that fault tree analysis is certainly a valuable tool for the troubleshooting of a complex facility. C1 NASA, Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP Zampino, EJ (reprint author), NASA, Glenn Res Ctr Lewis Field, MS 50-4,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 6 TC 6 Z9 6 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0149-144X BN 0-7803-6615-8 J9 P A REL MAI PY 2001 BP 16 EP 22 DI 10.1109/RAMS.2001.902435 PG 7 WC Computer Science, Software Engineering; Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BR83F UT WOS:000167729400003 ER PT S AU Clawson, JF Oberhettinger, D AF Clawson, JF Oberhettinger, D GP IEEE TI The lessons-learned process: An effective countermeasure against avoidable risk SO ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM, 2001 PROCEEDINGS SE PROCEEDINGS : ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT Annual Reliability and Maintainaability Symposium CY JAN 22-25, 2001 CL PHILADELPHIA, PENNSYLVANIA SP IEEE, SAE, IIE, SLE, EST, Soc Reliability Engineers DE lessons learned; information system; process improvement AB The engineering and operation of extremely complex and technically advanced systems pose unknown risks, and we must accept the likelihood of design errors throughout the life cycle. Expensive mistakes and lost opportunities are less acceptable, however, when it is discovered that the enterprise already knew how to avoid them. The lessons learned process performs a major role in communicating information essential to successful system design and development- especially under a compressed project schedule. This paper identifies success factors in the design and implementation of an effective lessons learned process and summarizes current research on tools for infusing enterprise-wide use of the lessons. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Clawson, JF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 122-107, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0149-144X BN 0-7803-6615-8 J9 P A REL MAI PY 2001 BP 94 EP 97 DI 10.1109/RAMS.2001.902448 PG 4 WC Computer Science, Software Engineering; Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BR83F UT WOS:000167729400016 ER PT J AU Aschwanden, MJ Poland, AI Rabin, DM AF Aschwanden, MJ Poland, AI Rabin, DM TI The new solar corona SO ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS LA English DT Review DE magnetic fields; plasma dynamics; coronal heating; solar flares; coronal mass ejections; extreme ultraviolet; soft X rays ID ACTIVE-REGION LOOPS; X-RAY TELESCOPE; CHROMOSPHERIC MAGNETIC RECONNECTION; STRUCTURES OBSERVING CAMPAIGN; SUNSPOT TRANSITION REGION; WHOLE-SUN-MONTH; TRANSEQUATORIAL INTERCONNECTING LOOPS; 3-DIMENSIONAL STEREOSCOPIC ANALYSIS; VERTICAL TEMPERATURE STRUCTURE; DIAGNOSTIC SPECTROMETER CDS AB We focus on new observational capabilities (Yohkoh, SoHO, TRACE), observations, modeling approaches, and insights into physical processes of the solar corona. The most impressive new results and problems discussed in this article can be appreciated from the movies available on the Annual Reviews website and at http://www.Imsal.com/pub/araa/araa.html. C1 Lockheed Martin Adv Technol Ctr, Solar & Astrophys Lab, Palo Alto, CA 94304 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Lockheed Martin Adv Technol Ctr, Solar & Astrophys Lab, Palo Alto, CA 94304 USA. EM aschwanden@lmsal.com; art.poland@gsfc.nasa.gov; douglas.rabin@gsfc.nasa.gov NR 305 TC 77 Z9 81 U1 2 U2 6 PU ANNUAL REVIEWS PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0066-4146 J9 ANNU REV ASTRON ASTR JI Annu. Rev. Astron. Astrophys. PY 2001 VL 39 BP 175 EP 210 DI 10.1146/annurev.astro.39.1.175 PG 44 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 480WU UT WOS:000171487200007 ER PT J AU Hauser, MG Dwek, E AF Hauser, MG Dwek, E TI The cosmic infrared background: Measurements and implications SO ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS LA English DT Review DE extragalactic background light; cosmology; COBE; galaxy evolution; cosmic chemical evolution; background fluctuations; TeV gamma-rays; integrated galaxy light ID SPECTRAL ENERGY-DISTRIBUTIONS; ACTIVE GALACTIC NUCLEI; STAR-FORMATION HISTORY; COBE DIRBE MAPS; GALAXY LUMINOSITY FUNCTION; GAMMA-RAY OBSERVATIONS; HUBBLE DEEP FIELD; ROCKET-BORNE OBSERVATION; HIGH-REDSHIFT GALAXIES; TELESCOPE IN-SPACE AB The cosmic infrared background records much of the radiant energy released by processes of structure formation that have occurred since the decoupling of matter and radiation following the Big Bang. In the past few years, data from the Cosmic Background Explorer (COBE) mission provided the first measurements of this background, with additional constraints coming from studies of the attenuation of TeV gamma -rays. At the same time, there has been rapid progress in resolving a significant fraction of this background with the deep galaxy counts at infrared wavelengths from the Infrared Space Observatory (ISO) instruments and at submillimeter wavelengths from the Submillimeter Common User Bolometer Array (SCUBA) instrument. This article reviews the measurements of the infrared background and sources contributing to it and discusses the implications for past and present cosmic processes. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Hauser, MG (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. EM hauser@stsci.edu; eli.dwek@gsfc.nasa.gov NR 288 TC 470 Z9 471 U1 1 U2 4 PU ANNUAL REVIEWS PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0066-4146 J9 ANNU REV ASTRON ASTR JI Annu. Rev. Astron. Astrophys. PY 2001 VL 39 BP 249 EP 307 DI 10.1146/annurev.astro.39.1.249 PG 63 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 480WU UT WOS:000171487200009 ER PT J AU Bell, JH Schairer, ET Hand, LA Mehta, RD AF Bell, JH Schairer, ET Hand, LA Mehta, RD TI Surface pressure measurements using luminescent coatings SO ANNUAL REVIEW OF FLUID MECHANICS LA English DT Review DE pressure-sensitive paints; optical measurement techniques; photogrammetry; aerodynamic loads; wind tunnel testing ID SENSITIVE PAINT MEASUREMENTS; TRANSITION-METAL COMPLEXES; TEMPERATURE-DEPENDENCE; SELF-ILLUMINATION; OXYGEN SENSORS; IDEALITY; POLYMER; LIFETIME; BEHAVIOR AB An optical technique is described that is often used nowadays to measure surface pressures on wind tunnel models and flight vehicles. The technique uses luminescent coatings, which are painted on the model surface, excited by light of appropriate wavelength, and imaged with digital cameras. The intensity of the emitted light is inversely proportional to the surface pressure. Hence, the surface pressures can be measured efficiently and affordably with a high spatial resolution. The theory and chemistry of how such coatings work and the parameters that affect them are presented. The required hardware and software are described, with emphasis on the different measurement systems and procedures. The various error sources are discussed, and correction schemes that can be used to minimize them are presented. Sample results, covering a wide range of conditions and applications, are presented and discussed. C1 NASA, Ames Res Ctr, Expt Phys Branch, Moffett Field, CA 94035 USA. RP Bell, JH (reprint author), NASA, Ames Res Ctr, Expt Phys Branch, Moffett Field, CA 94035 USA. NR 119 TC 204 Z9 209 U1 3 U2 45 PU ANNUAL REVIEWS PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0066-4189 J9 ANNU REV FLUID MECH JI Annu. Rev. Fluid Mech. PY 2001 VL 33 BP 155 EP 206 DI 10.1146/annurev.fluid.33.1.155 PG 60 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 414RM UT WOS:000167680000006 ER PT J AU Pashler, H Johnston, JC Ruthruff, E AF Pashler, H Johnston, JC Ruthruff, E TI Attention and performance SO ANNUAL REVIEW OF PSYCHOLOGY LA English DT Review DE dual-task interference; psychological refractory effect; task switching; attentional control; reflexive orienting ID ABRUPT VISUAL ONSETS; DUAL-TASK INTERFERENCE; MULTIPROCESSOR MODELS; SELECTIVE ATTENTION; 2 THINGS; CAPTURE; CONTINGENT; SEARCH; SET; OFFSETS AB Recent progress in the study of attention and performance is discussed, focusing on the nature of attentional control and the effects of practice. Generally speaking, the effects of mental set are proving more pervasive than was previously suspected, whereas automaticity is proving less robust. Stimulus attributes (e.g. onsets, transients) thought to have a "wired-in" ability to capture attention automatically have been shown to capture attention only as a consequence of voluntarily adopted task sets. Recent research suggests that practice does not have as dramatic effects as is commonly believed. While it may turn out that some mental operations are automatized in the strongest sense, this may be uncommon. Recent work on task switching is also described; optimal engagement in a task set is proving to be intimately tied to learning operations triggered by the actual performance of a new task, not merely the anticipation of such performance. C1 Univ Calif San Diego, Dept Psychol, La Jolla, CA 92093 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Pashler, H (reprint author), Univ Calif San Diego, Dept Psychol, La Jolla, CA 92093 USA. NR 77 TC 244 Z9 253 U1 3 U2 63 PU ANNUAL REVIEWS PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0066-4308 J9 ANNU REV PSYCHOL JI Annu. Rev. Psychol. PY 2001 VL 52 BP 629 EP 651 DI 10.1146/annurev.psych.52.1.629 PG 23 WC Psychology; Psychology, Multidisciplinary SC Psychology GA 410WB UT WOS:000167463100026 PM 11148320 ER PT S AU Li, JZ Cheung, SH Ning, CZ AF Li, JZ Cheung, SH Ning, CZ BE Lee, TP Wang, Q TI Nonlinearity effects of lateral density diffusion coefficient on gain-guided VCSEL performance SO APOC 2001: ASIA-PACIFIC OPTICAL AND WIRELESS COMMUNICATIONS: OPTOELECTRONICS, MATERIALS, AND DEVICES FOR COMMUNICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Asia-Pacific Optical and Wireless Communications Conference (APOC 2001) CY NOV 12-15, 2001 CL BEIJING, PEOPLES R CHINA SP SPIE, China Opt & Optoelectr Manufacturers Assoc, Minist Informat Ind, China Inst Commun, NEL NTT Electr Corp, Credit Suisse First Boston Technol Grp, China Telecom, Huawei Technologies, ZTE Corp, SANY Optilayer Co Ltd, Dateng Telecom, Photon Technol, O Net Commun Ltd, China Minist Sci & Technol, Alcatel, Corning, Australia Opt Soc, Beijing Univ Posts & Telecommun, Korea Assoc Photon Ind Dev, Optoelectr Ind Dev Assoc, Optoelectr Ind & Technol Dev Assoc, Opt Soc India, Opt Soc Japan, Opt Soc Korea, Photon Ind Dev Assoc, Photon Assoc, SPIE Asia Pacific Chapters, SPIE Tech Grp Opt Networks, Tsinghua Univ DE semiconductor laser; inhomogeneity; lateral carrier diffusion; nonlinearity; VCSEL ID SURFACE-EMITTING LASERS; CARRIER DIFFUSION; SEMICONDUCTOR-LASERS; BLOCH EQUATIONS; MODE; DYNAMICS AB Electron and hole diffusions in the plane of semiconductor quantum wells play an important part in the static and dynamic operations of semiconductor lasers. In this paper, we apply a hydrodynamic model developed from the semiconductor Bloch equations to numerically study the effects of nonlinearity in the diffusion coefficient on single mode operation and direct modulation of a gain-guided InGaAs/GaAs multiple quantum well laser, operating not too far from threshold. We found that a small diffusion coefficient is advantageous for lowering the threshold current and increasing the modulation bandwidth. Most importantly, the effects of nonlinearity in the coefficient can be approximately reproduced by replacing the coefficient with an effective constant diffusion coefficient, which corresponds roughly to the half height density of the density distribution. This conclusion is the same as in Ref. 8, but we will discuss the disagreements in reaching it. Finally, the beam profile is slightly modified in the nonlinear case. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Li, JZ (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, M-S T27A-1, Moffett Field, CA 94035 USA. NR 14 TC 0 Z9 0 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4310-7 J9 P SOC PHOTO-OPT INS PY 2001 VL 4580 BP 52 EP 59 DI 10.1117/12.444931 PG 4 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Optics SC Engineering; Materials Science; Optics GA BT78W UT WOS:000174066800009 ER PT B AU Clancy, DJ AF Clancy, DJ BE Macintosh, A Moulton, M Coenen, F TI Model-based system-level health management for reusable launch vehicles SO APPLICATIONS AND INNOVATIONS IN INTELLIGENT SYSTEMS VIII LA English DT Proceedings Paper CT 20th SGES International Conference on Knowledge Based Systems and Applied Artificial Intelligence (ES2000) CY DEC 11-13, 2000 CL CAMBRIDGE, ENGLAND SP SGES, British Comp Soc AB The next generation of reusable launch vehicles are expected to radically reduce the cost of accessing space thus enabling a broad range of endeavors including the commercialization of space and further manned exploration of the inner solar system. A reduction in operational costs requires more sophisticated techniques for monitoring and controlling the vehicle while in flight and techniques to streamline the ground processing of the vehicle. For both tasks, it is often necessary to synthesize information obtained from multiple subsystems to detect and isolate both hard failures and degraded component performance. C1 NASA, Ames Res Ctr, Riacs Corp, Moffett Field, CA 94035 USA. RP Clancy, DJ (reprint author), NASA, Ames Res Ctr, Riacs Corp, MS 269-2, Moffett Field, CA 94035 USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG LONDON LTD PI GODALMING PA SWEETAPPLE HOUSE CATTESHALL RD FARNCOMBE, GODALMING GU7 1NH, SURREY, ENGLAND BN 1-85233-402-9 PY 2001 BP 3 EP 16 PG 14 WC Computer Science, Artificial Intelligence SC Computer Science GA BR86H UT WOS:000167857300001 ER PT J AU Harvey, JE Krywonos, A Thompson, PL Saha, TT AF Harvey, JE Krywonos, A Thompson, PL Saha, TT TI Grazing-incidence hyperboloid-hyperboloid designs for wide-field x-ray imaging applications SO APPLIED OPTICS LA English DT Article ID INCIDENCE TELESCOPES; I TELESCOPE; ABERRATIONS; PERFORMANCE; ASTRONOMY AB The classical Welter type I grazing-incidence x-ray telescope consists of a paraboloidal primary mirror and a confocal hyperboloidal secondary mirror. This design exhibits stigmatic imaging on-axis hut suffers from coma, astigmatism, field curvature, and higher-order aberrations such as oblique spherical aberration. Wolter-Schwarzschild designs have been developed that strictly satisfy the Abbe sine condition and thus exhibit no spherical aberration or coma. However, for wide-field applications such as the solar x-ray imager (SXI), there is little merit in a design with stigmatic imaging on-axis. Instead, one needs to optimize some area-weighted-average measure of resolution over the desired operational field of view. This has traditionally been accomplished by mere despacing of the focal plane of the classical Welter type I telescope. Here we present and evaluate in detail a family of hyperboloid-hyperboloid grazing-incidence x-ray telescope designs whose wide-field performance is much improved over that of an optimally despaced Welter type I and even somewhat improved over that of an optimally despaced Wolter-Schwarzschild design. (C) 2001 Optical Society of America OCIS codes: 340.7440, 340.7470, 220.1000, 220.2740. C1 Univ Cent Florida, Ctr Res & Educ Opt & Lasers, Orlando, FL 32826 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Harvey, JE (reprint author), Univ Cent Florida, Ctr Res & Educ Opt & Lasers, POB 162700,4000 Cent Florida Blvd, Orlando, FL 32826 USA. EM harvey@creol.ucf.edu NR 34 TC 17 Z9 18 U1 1 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JAN 1 PY 2001 VL 40 IS 1 BP 136 EP 144 DI 10.1364/AO.40.000136 PG 9 WC Optics SC Optics GA 388VB UT WOS:000166202800016 PM 18356984 ER PT J AU Kim, MS McMurtrey, JE Mulchi, CL Daughtry, CST Chappelle, EW Chen, YR AF Kim, MS McMurtrey, JE Mulchi, CL Daughtry, CST Chappelle, EW Chen, YR TI Steady-state multispectral fluorescence imaging system for plant leaves SO APPLIED OPTICS LA English DT Article ID LASER-INDUCED FLUORESCENCE; LEAF GAS-EXCHANGE; CHLOROPHYLL FLUORESCENCE; GREEN PLANTS; CROP RESIDUE; STRESS; CO2; OZONE; BLUE; REFLECTANCE AB We present a detailed description of a laboratory-based multispectral fluorescence imaging system (MFIS) for plant leaves. Fluorescence emissions with 360-nm excitation are captured at four spectral bands in the blue, green, red, and far-red regions of the spectrum centered at 450, 550, 680, and 740 nm, respectively. Preliminary experiments conducted with soybean leaves treated with a herbicide (DCMU) and short-term exposures to moderately elevated tropospheric ozone environment demonstrated the utilities of the newly developed MFIS. In addition, with the aid of fluorescence images of normal soybean leaves, several mechanisms governing the fluorescence emissions are discussed. Imaging results illustrate the versatility of fluorescence imaging, which provides information on the spatial variability of fluorescence patterns over leaf samples. OCIS codes: 170.0110, 170.6280, 300.2140, 300.2530, 040.1520. C1 USDA, Beltsville Agr Res Ctr, Instrumentat & Sensing Lab, Beltsville, MD 20705 USA. USDA, Beltsville Agr Res Ctr, Remote Sensing & Modeling Lab, Beltsville, MD 20705 USA. Univ Maryland, Dept Nat Resource Sci & Landscape Architecture, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Kim, MS (reprint author), USDA, Beltsville Agr Res Ctr, Instrumentat & Sensing Lab, 10300 Baltimore AVe, Beltsville, MD 20705 USA. EM kimm@ba.ars.usda.gov NR 30 TC 56 Z9 58 U1 5 U2 12 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JAN 1 PY 2001 VL 40 IS 1 BP 157 EP 166 DI 10.1364/AO.40.000157 PG 10 WC Optics SC Optics GA 388VB UT WOS:000166202800019 PM 18356987 ER PT J AU Mann, DH Reanier, RE Peteet, DM Kunz, ML Johnson, M AF Mann, DH Reanier, RE Peteet, DM Kunz, ML Johnson, M TI Environmental change and Arctic Paleoindians SO ARCTIC ANTHROPOLOGY LA English DT Article; Proceedings Paper CT 64th Annual Meeting of the Society-for-American-Archaeology CY MAR 24-28, 1999 CL CHICAGO, ILLINOIS SP Soc Amer Archaeol ID YOUNGER DRYAS EVENT; BERING LAND-BRIDGE; SEA-LEVEL RECORD; NORTHERN ALASKA; NORTHWESTERN ALASKA; VEGETATION HISTORY; OCEAN CIRCULATION; ATMOSPHERIC C-14; LATE PLEISTOCENE; GREENLAND SNOW AB Intensive Paleoindian occupation of the Mesa site occurred between 10,300 and 9700 C-14 yr B.P. Was the timing of this occupation controlled by environmental changes? We investigated stratigraphic records of geomorphology and vegetation to describe how landscapes in the Arctic Foothills changed between 13,000 and 8000 C-14 yr B.P. Paleoindians were present during a time of rapid and sweeping changes in vegetation, slope erosion, floodplain dynamics, permafrost stability, and soil type. We speculate that Paleoindians moved into arctic Alaska to exploit population highs in large ungulates that in turn were triggered by landscape-scale, geomorphic disturbances caused by climate changes. Environmental changes slowed and rising sea levels flooded Alaska's continental shelves during the Early Holocene, causing summer temperatures to fall and precipitation to increase. A more stable climate and the prevalence of maritime air masses allowed the spread of tussock-tundra vegetation, which probably drove both the Paleoindians and their prey species out of the region. C1 Univ Alaska, Inst Arctic Biol, Fairbanks, AK 99775 USA. Univ Alaska, Alaska Quaternary Ctr, Fairbanks, AK 99775 USA. Reanier & Associates, Seattle, WA 98122 USA. NASA, Goddard Inst Space Studies, Palisades, NY 10964 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. Bur Land Management, Fairbanks, AK 99708 USA. Univ Alaska, Inst Marine Sci, Fairbanks, AK 99775 USA. RP Mann, DH (reprint author), Univ Alaska, Inst Arctic Biol, Fairbanks, AK 99775 USA. NR 115 TC 11 Z9 11 U1 2 U2 8 PU UNIV WISCONSIN PRESS PI MADISON PA JOURNAL DIVISION, 2537 DANIELS ST, MADISON, WI 53718 USA SN 0066-6939 J9 ARCTIC ANTHROPOL JI Arct. Anthropol. PY 2001 VL 38 IS 2 BP 119 EP 138 PG 20 WC Anthropology SC Anthropology GA 620UL UT WOS:000179550800008 ER PT S AU Milano, M Schmidhuber, J Koumoutsakos, P AF Milano, M Schmidhuber, J Koumoutsakos, P BE Dorffner, G Bischof, H Hornik, K TI Active learning with adaptive grids SO ARTIFICIAL NEURAL NETWORKS-ICANN 2001, PROCEEDINGS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT International Conference on Artificial Neural Networks (ICANN 2001) CY AUG 21-25, 2001 CL VIENNA UNIV TECHNOL, VIENNA, AUSTRIA SP Austrian Res Inst Artifical Intelligence HO VIENNA UNIV TECHNOL AB Given some optimization problem and a series of typically expensive trials of solution candidates taken from a search space, how can we efficiently select the next candidate? We address this fundamental problem using adaptive grids inspired by Kohonen's self-organizing map. Initially the grid divides the search space into equal simplexes. To select a candidate we uniform randomly first select a simplex, then a point within the simplex. Grid nodes are attracted by candidates that lead to improved evaluations. This quickly biases the active data selection process towards promising regions, without loss of ability to deal with "surprising" global optima in other areas. On standard benchmark functions the technique performs more reliably than the widely used covariance matrix adaptation evolution strategy. C1 ETH Zurich, Inst Computat Sci, Zurich, Switzerland. NASA, CTR, Moffett Field, CA 94035 USA. RP Milano, M (reprint author), ETH Zurich, Inst Computat Sci, Zurich, Switzerland. RI Koumoutsakos, Petros/A-2846-2008 OI Koumoutsakos, Petros/0000-0001-8337-2122 NR 5 TC 2 Z9 2 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-42486-5 J9 LECT NOTES COMPUT SC PY 2001 VL 2130 BP 436 EP 442 PG 7 WC Computer Science, Artificial Intelligence; Computer Science, Theory & Methods SC Computer Science GA BT43Y UT WOS:000173024600060 ER PT J AU Mays, DC Campbell, AB Nair, SS Miles, JB Thomas, GA AF Mays, DC Campbell, AB Nair, SS Miles, JB Thomas, GA TI Thermal technologies for space suits SO ASHRAE JOURNAL LA English DT Article AB Sustaining life in the harsh vacuum of space and in the low-pressure carbon dioxide Martian atmosphere is challenging and complex. Additionally, there exists a large range of effective temperatures, and the ever-present danger of micrometeorite and space debris impact. On Mars, as on Earth, wide climate differences exist at different points on the planet and temperatures vary by several degrees even from the astronaut's feet to head levels. Astronauts have reported cold discomfort during Extra-vehicular Activities (EVAs), which distracted them from their work.(1) The Martian atmosphere is made up of mostly carbon dioxide at a pressure of 0.123 psia (848.1 Pa), far less than the Earth's atmospheric pressure of 14.7 psia (101.4 kPa). These conditions must be quantified so engineers can develop and optimize a space suit system for a given task. The primary factors to be considered are:(2). C1 Honeywell Inc, Torrance, CA 90501 USA. Univ Missouri, Dept Mech & Aerosp Engn, Columbia, MO 65211 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Mays, DC (reprint author), Honeywell Inc, Torrance, CA 90501 USA. NR 9 TC 0 Z9 0 U1 0 U2 2 PU AMER SOC HEATING REFRIGERATING AIR-CONDITIONING ENG, INC, PI ATLANTA PA 1791 TULLIE CIRCLE NE, ATLANTA, GA 30329 USA SN 0001-2491 J9 ASHRAE J JI ASHRAE J. PD JAN PY 2001 VL 43 IS 1 BP 25 EP + PG 9 WC Thermodynamics; Construction & Building Technology; Engineering, Mechanical SC Thermodynamics; Construction & Building Technology; Engineering GA 392WN UT WOS:000166435700013 ER PT S AU Condon, GL Pearson, DJ AF Condon, GL Pearson, DJ BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI The role of humans in libration point missions with specific application to an Earth-Moon libration point gateway station SO ASTRODYNAMICS 2001, PTS I-III SE Advances in the Astronautical Sciences LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB Human presence in space has already shown significant benefits. Human crews have repaired and re-deployed ailing spacecraft, such as Hubble Space Telescope, Solar Max satellite, and Leasat 3. Astronauts provided enhancements to the originally myopic Hubble Space Telescope and, on a separate occasion, replaced critical failed control gyros, thus saving a national resource that now continues to provide tremendous scientific discovery. In addition, human crews have retrieved both ailing spacecraft, such as Westar and Palapa, and experiment platforms such as the Long Duration Exposure Facility (LDEF). The notion of human missions to libration points has been proposed for more than a generation. Satellite servicing of science packages strategically located at libration points provides but one of numerous potential mission concepts. Other human mission concepts have examined the viability and utility of human missions in the vicinity of libration points in the Sun-Earth and Earth-Moon systems. This paper addresses the role of humans in libration point space missions and, in particular, mission design considerations for in example Earth-Moon libration point gateway station. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Condon, GL (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 9 TC 4 Z9 4 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 95 EP 110 PN 1-3 PG 16 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400006 ER PT S AU Markley, FL AF Markley, FL BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Attitude representations for Kalman filtering SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID INTEGRATORS; EQUATIONS; DYNAMICS AB The four-component quaternion has the lowest dimensionality possible for a globally nonsingular attitude representation, it represents the attitude matrix as a homogeneous quadratic function, and its dynamic propagation equation is bilinear in the quaternion and the angular velocity. The quaternion is required to obey a unit norm constraint, though, so Kalman filters often employ a quaternion for the global attitude estimate and a three-component representation for small errors about the estimate. We consider these mixed attitude representations for both a first-order Extended Kalman Filter and a second-order filter, as well as for quaternion-norm-preserving attitude propagation. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Syst Engn Branch, Greenbelt, MD 20771 USA. RP Markley, FL (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Syst Engn Branch, Mail Code 571, Greenbelt, MD 20771 USA. NR 33 TC 2 Z9 4 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 133 EP 151 PN 1-3 PG 19 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400008 ER PT S AU Harman, RR Bar-Itzhack, IY Markley, FL AF Harman, RR Bar-Itzhack, IY Markley, FL BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Calibration of the skewed aqua satellite gyros SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB This work presents a new approach to gyro calibration where the spacecraft dynamics equation, attitude measurements, and the gyro outputs are used in a Pseudo linear Kalman filter that estimates the calibration parameters. This work also presents an algorithm for calibrating a quadruplet rather than the customary triad gyro set. In particular, a new misalignment error model is derived for this case. The new calibration algorithm is applied to the EOS-AQUA satellite gyros. The effectiveness of the new algorithm is demonstrated through simulations. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Flight Dynam Anal Branch, Greenbelt, MD 20771 USA. RP Harman, RR (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Flight Dynam Anal Branch, Code 572, Greenbelt, MD 20771 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 199 EP 212 PN 1-3 PG 14 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400012 ER PT S AU Wong, E Breckenridge, W Boussalis, D Brugarolas, P Bayard, DS Spanos, J Singh, G AF Wong, E Breckenridge, W Boussalis, D Brugarolas, P Bayard, DS Spanos, J Singh, G BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Post-flight attitude reconstruction for the Shuttle Radar Topography Mission SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The Shuttle Radar Topography Mission is the first mission to provide high accuracy near-global topographic coverage of the Earth's land surface using a long-baseline interferometry approach. The mission involves a large space structure (60 meter mast) deployable from the Shuttle payload bay and requires precision attitude and position determination to are-second and millimeter levels. A description of the ground software system architecture and data processing methodology for the post-flight reconstruction of the attitudes and positions of the outboard and inboard antennas is provided. Unexpected problems caused by sensor noise, alignment errors, and failed mast dampers posted big challenges to post-flight attitude reconstruction. As a result, various attitude reconstruction techniques for minimizing the radar height errors, such as estimation of structural misalignments, data interpolation, time synchronization, estimator and model tuning, and nonlinear filtering were introduced. Results indicated the requirement of 16 meters absolute vertical height accuracy can be met, and the various attitude reconstruction methods had contributed to an improvement of relative height accuracy from 15 to around 3 meters. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wong, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 1 Z9 1 U1 1 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 213 EP 235 PN 1-3 PG 23 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400013 ER PT S AU Luquette, RJ Sanner, RM AF Luquette, RJ Sanner, RM BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI A non-linear approach to spacecraft formation control in the vicinity of a collinear libration point SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB An expanding interest in mission design strategies that exploit libration point regions demands the continued development of enhanced, efficient, control algorithms for station-keeping and formation maintenance. This paper discusses the development of a nonlinear, formation maintenance, control algorithm for trajectories in the vicinity of a libration point, However, the formulation holds for any trajectory governed by the equations of motion for the restricted three body problem. The control law guarantees exponential convergence, based on a Lyaponov analysis. FreeFlyer(R) and MATLAB(R) provide the simulation environment for controller performance evaluation. The simulation, modeled after the MAXIM Pathfinder mission, maintains the relative position of a "follower" spacecraft with respect to a "leader" spacecraft, stationed near the L2 libration point in the Sun-Earth system. Evaluation metrics are fuel usage and tracking accuracy. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Greenbelt, MD 20771 USA. RP Luquette, RJ (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Code 572, Greenbelt, MD 20771 USA. NR 3 TC 5 Z9 5 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 437 EP 445 PN 1-3 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400026 ER PT S AU Goodson, T AF Goodson, T BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Monte-Carlo maneuver analysis for the microwave anisotropy probe SO ASTRODYNAMICS 2001, PTS I-III SE Advances in the Astronautical Sciences LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB Maneuver analysis for the lunar-swingby phase of the Microwave Anisotropy Probe mission trajectories is presented. This phase spans from launch to the lunar swingby; maneuvers after the swingby are ignored. The analysis is complicated by the need to replicate the nominal trajectory in a different design tool. The results of this trajectory replication are presented, followed by the results of monte-carlo maneuver simulations. The results are subject to two important assumptions: that linearization is valid (as the software used for the monte-carlo simulation, LAMBIC, is based on a linearization of the trajectory about the nominal) and that the planned human-in-the-loop lunar targeting may be approximated by targeting to a fixed aimpoint. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Goodson, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 447 EP 464 PN 1-3 PG 18 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400027 ER PT S AU Christensen, EJ Williams, BG Ionasescu, R AF Christensen, EJ Williams, BG Ionasescu, R BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Near-earth solar sail navigation: Preliminary results SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID MISSIONS AB Preliminary analyses have been conducted to assess the accuracy of the measured acceleration acting on a solar sail in a low-Earth orbit. The studies focused on a sun-synchronous Earth orbiter in a nearly circular, similar to1000 km altitude orbit. Perturbations to this orbit were simulated using a 40mx40m square solar sail to propel a 157 kg spacecraft into a slowly expanding spiral orbit. Although the forces exerted by the sail are relatively small, it was found that they could be estimated to within similar to6x10(-4) mm/s(2), in similar to3 days with only one pass of Deep Space Network (DSN) tracking per day. C1 CALTECH, Jet Prop Lab, Navigat & Miss Design Sect, Pasadena, CA 91109 USA. RP Christensen, EJ (reprint author), CALTECH, Jet Prop Lab, Navigat & Miss Design Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 755 EP 764 PN 1-3 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400047 ER PT S AU Williams, BG Antreasian, PG Bordi, JJ Carranza, E Chesley, SR Helfrich, CE Miller, JK Owen, WM Wang, TC AF Williams, BG Antreasian, PG Bordi, JJ Carranza, E Chesley, SR Helfrich, CE Miller, JK Owen, WM Wang, TC BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Navigation for NEAR Shoemaker: The first spacecraft to orbit an asteroid SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID MISSION; EROS AB When the NEAR Shoemaker spacecraft began its orbit about the asteroid 433 Eros on February 14, 2000, it marked the beginning of many firsts for deep space navigation, Among these were the design and estimation techniques that were necessary to plan and execute an orbit about an irregularly shaped small body. Knowledge of the mass, gravity distribution, and spin state of Eros had to be quickly improved on final approach in order to predict the effect of trajectory correction maneuvers for capture and orbit control around Eros. This required the use of optical landmark tracking, which used pictures of craters on Eros as landmark information, in addition to the more traditional radio metric tracking from NASA's Deep Space Network. The operational use of optical landmark tracking was another navigation first for the NEAR mission. As part of the ongoing effort to improve the Eros physical model, altimeter data from the NEAR laser range instrument was also processed and analyzed. This paper describes the navigation strategy and results for the rendezvous and orbit phases of the NEAR mission. Included are descriptions of the new techniques developed to deal with navigation challenges encountered during the year-long orbit phase. The orbit phase included circular orbits down to 35 km radius and elliptical orbits that targeted overflights to within 2.7 km above the surface. Many of these methods should prove useful for navigation of future missions to asteroids and comets. C1 CALTECH, Jet Prop Lab, Navigat & Mission Design Sect, Pasadena, CA 91109 USA. RP Williams, BG (reprint author), CALTECH, Jet Prop Lab, Navigat & Mission Design Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 2 Z9 2 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 973 EP 988 PN 1-3 PG 16 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400061 ER PT S AU Antreasian, PG Chesley, SR Miller, JK Bordi, JJ Williams, BG AF Antreasian, PG Chesley, SR Miller, JK Bordi, JJ Williams, BG BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI The design and navigation of the NEAR Shoemaker landing on Eros SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID SPACECRAFT; MISSION AB After a 4.5 hour controlled descent using five open-loop maneuvers on February 12, 2001, the Discovery-class NEAR Shoemaker spacecraft successfully landed on the surface of Eros becoming the first spacecraft ever to touchdown on an asteroid. This landing was made more extraordinary by the fact that the spacecraft was not designed fur landing and it remained in communication with NASA's Deep Space Network afterwards. Tile descent trajectory was designed primarily to acquire as many close range high-resolution images (< 1 km) as possible while providing optimal viewing geometries and secondarily to ensure the safety of the spacecraft by minimizing its impact velocity. Since the spherical harmonic representation of Eros' gravity diverges below the sphere circumscribing the asteroid (< 18 km), a polyhedral gravity field based on our Eros shape determination was used for integrating the trajectory below this limit. This paper discusses the design, navigation and the Monte Carlo error analyses that were critical to the design of this landing scenario. Also described are preliminary reconstructions of tile landing trajectory and site using radio metric, optical landmark and laser ranging tracking data, which determined the characteristics of the landing to be within the expected dispersions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Antreasian, PG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 989 EP 1015 PN 1-3 PG 27 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400062 ER PT S AU Owen, WM Wang, TC Harch, A Bell, M Peterson, C AF Owen, WM Wang, TC Harch, A Bell, M Peterson, C BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Near optical navigation at Eros SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID NEARS AB Successful navigation of the spacecraft NEAR Shoemaker during its orbit phase at the asteroid Eros depended critically on optical navigation. The irregular shape of Eros and its large apparent size precluded the use of traditional optical navigation techniques whereby the center of mass of a target body is located relative to stars in onboard imaging. Rather, optical navigation during NEAR's orbit phase consisted of locating small craters in images of Eros' surface and using those landmarks to infer Eros' rotation state, the body-fixed coordinates of each landmark, and the trajectory of the spacecraft. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Owen, WM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 1075 EP 1087 PN 1-3 PG 13 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400066 ER PT S AU Lyons, DT AF Lyons, DT BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Aerobraking automation options SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB Two interplanetary missions have successfully used aerobraking to provide a velocity change of 1200 m/s. The first was the Magellan mission to Venus, where atmospheric drag was used to shrink the orbit late in the extended mission. The second was the Mars Global Surveyor (MGS) mission to Mars. Both of these missions required extensive commanding from the ground in order to keep the activities on the spacecraft, especially those during the pass through the atmosphere, synchronized with the actual orbit. This paper will summarize some recent work to automate most of the commanding intensive activities associated with aerobraking. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lyons, DT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 301-140L, Pasadena, CA 91109 USA. NR 18 TC 3 Z9 4 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 1231 EP 1246 PN 1-3 PG 16 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400075 ER PT S AU Jah, M AF Jah, M BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI A proposed use of accelerometer data for autonomous aerobraking at Mars SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB For any interplanetary mission, there are certain types of data that are used as a means of determining both the position and velocity of a spacecraft. NASA's Deep Space Network (DSN) is employed for the purpose of transmitting and receiving data to and from the spacecraft, respectively. For this exchange of information to take place, both the DSN and spacecraft antennae must be pointed towards each other. This mutual geometry is not maintained throughout aerobraking, specifically while the spacecraft is within the atmosphere. Some spacecraft are equipped with an Inertial Measurement Unit (IMU), which typically is comprised of gyroscopes and accelerometers, The accelerometers provide data pertaining to the spacecraft's acceleration. Since the spacecraft loses telemetry during the drag pass, this research focuses upon the possibility of using accelerometer data as a means of augmenting the current state knowledge of the spacecraft. This knowledge could also assist in obtaining best estimates for subsequent periapse times and altitudes (integral aspect of aerobraking operations). The end goal is to achieve some level of autonomy concerning aerobraking operations. To this end, an improved navigation capability is needed. Part of this capability may result from the use of accelerometer data. This paper addresses the road map by which this goal may be implemented; a methodology is given by which an improvement to spacecraft navigation accuracy may be achieved by including accelerometer measurements as observations. C1 CALTECH, Jet Prop Lab, Navigat & Mission Design Sect, Pasadena, CA 91109 USA. RP Jah, M (reprint author), CALTECH, Jet Prop Lab, Navigat & Mission Design Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 1247 EP 1256 PN 1-3 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400076 ER PT S AU Ilanna, JL Tolson, RH AF Ilanna, JL Tolson, RH BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Approaches to autonomous aerobraking at Mars SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB Planetary atmospheric aerobraking was first performed during the extended part of the Magellan mission to Venus. The technique proved so efficient at providing significant reductions in orbital energy without major propulsive utilization, that it was based lined for the Mars Global Surveyor (MGS) mission. The technique was planned for the failed Mars 1998 Polar Orbiter mission, will be utilized for the Mars 2001 Odyssey mission, and will most likely be incorporated in every future Mars orbiting mission. For all of these missions, aerobraking requires intensive manpower during operations, At Mars, orbit to orbit variations in atmospheric density at aerobraking altitudes proved to be as large as 35% 1-sigma. To provide safe and efficient aerobraking, both navigation and spacecraft system teams must be extremely diligent in updating spacecraft sequences and performing periapsis raise or lower maneuvers. Automating the process with onboard measurements could significantly reduce the operational burden and, in addition, could reduce the potential for human error. Two levels of automation are presented and validated using part of the MGS aerobraking sequence and a simulated Mars Odyssey sequence. The simplest method only provides the capability to update the onboard sequence. This method utilizes onboard accelerometer measurements to estimate the change in orbital period during an aerobraking pass and thereby estimates the beginning of the next aerobraking sequence. Evaluation of the method utilizing MGS accelerometer data showed that the time of the next periapsis can be estimated to within 25% 3sigma of the change in the orbital period due to drag. The second approach provides complete onboard orbit propagation. A low order gravity model is proposed that is sufficient to provide periapsis altitude predictions to within 100-200 meters over 3 orbits. Accelerometer measurements are used as part of the trajectory force model while the s/c is in the atmosphere. C1 George Washington Univ, JIAFS, Langley Res Ctr, Hampton, VA 23681 USA. RP Ilanna, JL (reprint author), George Washington Univ, JIAFS, Langley Res Ctr, MS 335, Hampton, VA 23681 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 1257 EP 1272 PN 1-3 PG 16 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400077 ER PT S AU Dwyer, AM Tolson, RH Munk, MM Tartabini, PV AF Dwyer, AM Tolson, RH Munk, MM Tartabini, PV BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Development of a Monte Carlo mars-gram model for mars 2001 aerobraking simulations SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID GLOBAL SURVEYOR AB Atmospheric density data taken during the Mars Global Surveyor (MGS) mission showed significant variability over the altitude ranges of interest for aerobraking, This paper presents the method by which MGS data was used to determine the statistical distribution of mean density, and the amplitude and phase of stationary atmospheric waves as a function of latitude. Using this information, a model was developed to implement the variations into Monte Carlo simulations for future missions to Mars, specifically the Mars 2001 Odyssey aerobraking mission scheduled begin in October, 2001. An example of Monte Carlo results for the Mars 2001 aerobraking mission are shown. C1 George Washington Univ, Joint Inst Advancement Flight Sci, NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Dwyer, AM (reprint author), George Washington Univ, Joint Inst Advancement Flight Sci, NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 7 TC 3 Z9 3 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 1293 EP 1308 PN 1-3 PG 16 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400079 ER PT S AU Spencer, DA Bell, JL Beutelschies, G Mase, RA Smith, JC AF Spencer, DA Bell, JL Beutelschies, G Mase, RA Smith, JC BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI 2001 mars odyssey mission design SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The 2001 Mars Odyssey spacecraft was launched on April 7, 2001 and will capture into Mars orbit on October 24, 2001. Following an aerobraking phase, the orbiter will conduct a science and relay mission for two Mars years. An overview of the Odyssey mission design and navigation approach is presented. Status of the mission to date (three months before arrival at Mars) is provided. The mission strategies for Mars Orbit Insertion, aerobraking, and the science and relay phases are described. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Spencer, DA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 2 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 1329 EP 1349 PN 1-3 PG 21 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400081 ER PT S AU Vincent, MA AF Vincent, MA BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Explanation and history of the new solar cycle/atmospheric model used in mars planetary protection analysis SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID GLOBAL STRUCTURE; CYCLE VARIATION; SURVEYOR; WINDS AB In December 2000, it was decided to update the solar cycle/Mars atmosphere model coded in the software used to do the orbit lifetime aspects of Planetary Protection (PP) analysis (Vincent, 2000). The old model was based on analysis done for the Mars Observer mission in the early to mid-1980's. Since then the atmospheric models of the scientific community have been refined. In particular, the empirical measurements obtained from the accelerometer on board the Mars Global Surveyor (MGS) mission during its aerobraking phase have been included. The new model used in the PP analysis is fitted to match the recent scientific results. This report is an expanded version of an earlier memo (Vincent 2001) written to justify the use of this model. The new model is shown to be valid while still retaining some conservatism. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vincent, MA (reprint author), CALTECH, Jet Prop Lab, Mail Stn 301-140L,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 23 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 1599 EP 1613 PN 1-3 PG 15 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400099 ER PT S AU Esposito, P Graat, E Demcak, S Baird, D Alwar, V AF Esposito, P Graat, E Demcak, S Baird, D Alwar, V BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Mars global surveyor: Mapping orbit evolution and control throughout one Mars year SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB This paper presents the evolution and control of Mars Global Surveyor's (MGS) mapping orbit throughout one Mars year of the primary mapping mission. Starting on 3/9/99, after the completion of the second phase of aerobraking, this phase had a duration of 695 days or 8,505 orbits and ended on 2/1/01. At present, the project is in an extended mission which shall end on 4/22/02. The MGS orbit is the first short period, low altitude, nearly circular and polar, frozen-orbit and sun-synchronous orbiter of Mars. The two major effects influencing the orbit evolution are: a) small, frequent and nearly instantaneous velocity perturbations induced by the spacecraft's angular momentum desaturations (AMD) and b) the gravity field of Mars. The accumulated effect of AMDs has had a significant effect on the semi-major axis and, therefore, on the ground track walk and the uniform distribution of the ground tracks. In addition, predicting the influence of AMDs directly impacts the accuracy of the predicted time of descending equator crossings, Tdeqx, which is necessary for precise image targeting. Current plans for MGS are: a) continue science observations at least until 4/22/02, b) assist Mars Odyssey during aerobraking as an early warning system for the detection of dust storms, c) obtain high resolution images of potential landing sites for the Mars Exploration Rover Mission (MER) and d) to act as a relay satellite for telemetry transmission during the descent phase of the two MER rovers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Esposito, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 1615 EP 1632 PN 1-3 PG 18 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400100 ER PT S AU Rush, B Bhaskaran, S Synnott, SP AF Rush, B Bhaskaran, S Synnott, SP BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Improving mars approach navigation using optical data SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB An important objective of future Mars missions is to land with increasing accuracy at the surface, requiring precise targeting of the trajectory at entry. The approach navigation accuracies obtained with radio data can be improved with optical data, using satellite images against a star back-round to pinpoint the spacecraft's Mars-centered state. This paper presents covariance studies showing that these data can produce entry accuracies better than 0.1 degrees in flight-path angle and better than one km in position. Simulations validate these results, using a realistic Phobos model, and considering the effects on the solution of errors in the model that affect the appearance of Phobos. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rush, B (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 1651 EP 1660 PN 1-3 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400102 ER PT S AU Gaskell, RW AF Gaskell, RW BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Automated landmark identification for spacecraft navigation SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB An integrated approach to surface relative optical landmark tracking for spacecraft is being developed. Landmarks are defined as full digital topography/albedo maps and are determined from previous imaging and navigation data. Initially, this technique will speed up ground based optical navigation. Ultimately, it will enable on-board trajectory determination during orbital and landing maneuvers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gaskell, RW (reprint author), CALTECH, Jet Prop Lab, Mail Stn 301-150,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 1749 EP 1756 PN 1-3 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400108 ER PT S AU Salama, A Soroosh, A Martin-Mur, T Paredes, E AF Salama, A Soroosh, A Martin-Mur, T Paredes, E BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI TOPEX/Poseidon and Jason-1 coordinated navigation SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB This paper presents the results of the TOPEX/Poseidon and Jason-1 coordinated navigation effort performed by the TOPEX/Poseidon navigation team. Three mission phases are considered. First, coordinated navigation effort during Jason acquisition phase is presented. Formation flying during Jason cross calibration and validation phase is then discussed. Finally, the tandem mission is analyzed. It is the phase, which follows calibration during which the two satellites repeat different ground track grid. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Salama, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 1769 EP 1782 PN 1-3 PG 14 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400110 ER PT S AU Strange, NJ Sims, JA AF Strange, NJ Sims, JA BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Methods for the design of V-infinity leveraging maneuvers SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB V-infinity leveraging maneuvers are intended to change the v-infinity of a spacecraft during transfers between flybys of a gavity-assist body. This paper considers these leveraging transfers in three categories: resonant, non-resonant, and pi-transfers. Methods are developed for the analysis of each type of transfer and its associated leveraging maneuver. An analytic solution is developed for inclined leveraging transfers. A Tisserand graphical method is presented for the analysis of planar leveraging transfers. These methods have application to tour design at Saturn and Neptune, study of interplanetary trajectories such as DeltaV-EGA (DeltaV Earth Gravity Assist) trajectories, and study of lunar gravity assist transfers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Strange, NJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 7 Z9 8 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 1959 EP 1976 PN 1-3 PG 18 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400122 ER PT S AU DeFazzio, RL Owens, S Good, S AF DeFazzio, RL Owens, S Good, S BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Follow that satellite: EO-1 maneuvers into close formation with Landsat-7 SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB As the Landsat-7 (LS-7) spacecraft continued NASA's historic program of earth imaging begun over three decades ago, NASA launched the Earth Observing -1 (EO-1) spacecraft carrying examples of the next generation of LS instruments. The validation method for these instruments was to have EO-1 fly in a close formation behind LS-7 on the same World Reference System (WRS) path. From that formation hundreds of near-coincident images would be taken by each spacecraft and compared to evaluate improvements in the EO-1 instruments. This paper will address the mission analysis required to launch and maneuver EO-1 into the formation with LS-7 where instrument validation was to occur plus a summary of completing the formation acquisition. EO-1 is required to operate one minute + / - 6 seconds behind LS-7 during the period of co-fly imaging with a cross track separation of within + / - 3 kilometers. This separation time can also be stated as a one minute + / - 6 seconds time difference in the Mean Local Time (MLT) at the descending nodes. Achieving the required MLT is heavily dependent on the time of launch. The EO-1 launch window, which had to accommodate the dual payloads of EO-1 and SAC-C, was very limited ranging from 0 to 22 seconds over the 16-day LS-7 WRS repeat cycle during which EO-1 was launched. Each EO-1 launch opportunity occurred on a different day of a LS-7 16-day repeat cycle and required a separate and distinct maneuver profile. These profiles varied significantly in duration and amount of onboard propellant required to achieve them. EO-1 launched on a day judged to have "medium" resource requirements for achieving the formation with LS-7. To phase EO-1 one minute behind LS-7 in the along track direction, a series of altitude adjusts separated by specific drift intervals was executed. Additional maneuvers slightly changed the EO-1 inclination to maintain the MLT requirements, Orbit maneuvers were planned and executed within errors of less than 1.5 percent and propellant usage was near nominal, i.e. consuming 3.4 kilograms out of a launch and early-orbit 3-sigma propellant budget of 11 kilograms. While the pre-launch 3-sigma propellant budget allowed for 1+ years of EO-1 mission life, the success of EO-1 launch and early orbit operations provided sufficient propellant for nearly 4 years of on-orbit operations, Special action taken during the EO-1 maneuver period involved some maneuver re-planning to reduce concerns about a potential close approach between EO-1 and LS-7. The result of this re-planning was a safer close approach and improvement in future formation acquisition planning. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP DeFazzio, RL (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 1 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 2095 EP 2113 PN 1-3 PG 19 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400131 ER PT S AU Chodas, PW Chesley, SR Chamberlin, AB Yeomans, DK AF Chodas, PW Chesley, SR Chamberlin, AB Yeomans, DK BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Automated detection of potentially hazardous near-earth encounters SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB We are now implementing an automatic process for updating orbital solutions for NEOs and detecting those objects that have an Earth collision probability greater than about 10(-6). Since some NEO orbits are very uncertain, nonlinearites can be large, and both Monte Carlo and multiple solutions methods are used for detecting possible Earth close encounters in these cases. Close approach data are collated and analyzed on the impact plane for each encounter. Automation using robust algorithms is essential because of the large number of objects and possible close approaches. This paper discusses the techniques and algorithms used, and presents a few examples of asteroids which for a time had significantly non-zero probabilities of colliding with the Earth. In most of these cases, subsequent observations led to more precise orbital solutions and eliminated the possibility of collision. C1 CALTECH, Jet Prop Lab, Navigat & Miss Design Sect, Pasadena, CA 91109 USA. RP Chodas, PW (reprint author), CALTECH, Jet Prop Lab, Navigat & Miss Design Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 2239 EP 2254 PN 1-3 PG 16 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400139 ER PT S AU Sims, JA AF Sims, JA BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Reducing the earth entry velocity for a comet nucleus sample return mission SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB Direct return to Earth after rendezvousing with a comet entails a very high entry velocity. Several methods for reducing the entry velocity, including using additional propellant on a direct return or using planetary gravity assists, are presented. The entry velocity can be reduced to a regime commensurate with cur-rent deep space sample return missions. The best method is a function of the mission parameters and target comet. C1 CALTECH, Jet Prop Lab, Navigat & Miss Design Sect, Pasadena, CA 91109 USA. RP Sims, JA (reprint author), CALTECH, Jet Prop Lab, Navigat & Miss Design Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 2255 EP 2268 PN 1-3 PG 14 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400140 ER PT S AU Heaton, AF Longuski, JM AF Heaton, AF Longuski, JM BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI The feasibility of a Galileo-Style tour of the uranian satellites SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB Gravity-assist trajectories have been a key to outer Solar System exploration. In particular, the gravity-assist tour of the Jovian satellites has contributed significantly to the success of the Galileo mission. A comparison of the Jovian system to the Uranian system reveals that the two possess similar satellite/planet mass ratios, Tisserand graphs of the Uranian system also indicate the potential for tours at Uranus. In this paper, we devise tour strategies and design a prototypical tour of the Uranian satellites, proving that tours at Uranus are feasible. C1 Purdue Univ, Sch Aeronaut & Astronaut, W Lafayette, IN 47907 USA. RP Heaton, AF (reprint author), NASA, George C Marshall Space Flight Ctr, Miss Planning Grp, Huntsville, AL 35812 USA. NR 12 TC 0 Z9 0 U1 1 U2 2 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 2285 EP 2296 PN 1-3 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400142 ER PT S AU Sweetser, TF Sauer, CG AF Sweetser, TF Sauer, CG BE Spencer, DB Seybold, DB Misra, AK Lisowski, RJ TI Advanced propulsion options for missions to the Kuiper belt SO ASTRODYNAMICS 2001, PTS I-III SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB Ever since Kuiper Belt Objects (KBOs) were discovered in the distant reaches of the solar system, they have been objects of desire for planetary scientists. This paper examines different forms of advanced propulsion to see how useful they would be for fast flyby missions to KBOs. Only those unproven technologies that could be available within the next ten years or so are considered, and their performance is compared to chemical and solar electric propulsion. To sum up, solar sails look good, thermal desorption doesn't seem to help enough for this application to justify its development, and mini-magnetospheric plasma propulsion (M2P2) is a dark horse that might be a big winner. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sweetser, TF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-488-5 J9 ADV ASTRONAUT SCI PY 2001 VL 109 BP 2297 EP 2306 PN 1-3 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BV23N UT WOS:000178285400143 ER PT S AU Mazzarella, JM Madore, BF Helou, G AF Mazzarella, JM Madore, BF Helou, G CA NED Team BE Starck, JL Murtagh, FD TI Capabilities of the NASA/IPAC extragalactic database in the era of a global virtual observatory SO ASTRONOMICAL DATA ANALYSIS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Astronomical Data Analysis CY AUG 02-03, 2001 CL SAN DIEGO, CA SP SPIE DE databases; information retrieval; knowledge discovery; classification; data mining ID MAPS AB We review the capabilities of the NASA/IPAC Extragalactic Database (NED, http: //ned.ipac.caltech.edu) for information retrieval and knowledge discovery in the context of a globally distributed virtual observatory. Since it's inception in 1990, NED has provided astronomers world-wide with the results of a systematic cross-correlation of catalogs covering all wavelengths, along with thousands of extragalactic observations culled from published journal articles. NED is continuously being expanded and revised to include new catalogs and published observations, each undergoing a process of cross-identification to capture the current state of knowledge about extragalactic sources in a panchromatic fashion. In addition to assimilating data from the literature, the team is incrementally folding in millions of observations from new large-scale sky surveys such as 2MASS, NVSS, APM, and SDSS. At the time of writing the system contains over 3.3 million unique objects with 4.2 million cross-identifications. We summarize the recent evolution of NED from its initial emphasis on object name-, position-, and literature-based queries into a research environment that also assists statistical data exploration and discovery using large samples of objects. Newer capabilities enable intelligent 'Web mining' of entries in geographically distributed astronomical archives that are indexed by object names and positions in NED, sample building using constraints on redshifts, object types and other parameters, as well as image and spectral archives for targeted or serendipitous discoveries. A pilot study demonstrates how NED is being used in conjunction with linked survey archives to characterize the properties of galaxy classes to form a training set for machine learning algorithms; an initial goal is production of statistical likelihoods that newly discovered sources belong to known classes, represent statistical outliers, or candidates for fundamentally new types of objects. Challenges and opportunities for tighter integration of NED capabilities into data mining tools for astronomy archives are also discussed. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. RP Mazzarella, JM (reprint author), CALTECH, Jet Propuls Lab, MS 100-22, Pasadena, CA 91125 USA. NR 8 TC 7 Z9 7 U1 0 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4191-0 J9 P SOC PHOTO-OPT INS PY 2001 VL 4477 BP 20 EP 34 DI 10.1117/12.447177 PG 15 WC Astronomy & Astrophysics; Computer Science, Artificial Intelligence; Computer Science, Information Systems SC Astronomy & Astrophysics; Computer Science GA BT68L UT WOS:000173724200003 ER PT B AU Jones, J Maks, L Fishman, M Grella, V Kerbel, U Misra, D Pell, V AF Jones, J Maks, L Fishman, M Grella, V Kerbel, U Misra, D Pell, V BE Harnden, FR Primini, FA Payne, HE TI Tools for coordinating planning between observatories SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS X SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 10th Annual Conference for Astronomical Data Analysis Software and Systems (ADASS 2000) CY NOV 12-15, 2000 CL BOSTON, MA SP Akibia Inc, Canada France Hawaii Telescope, NASA, Space Telescope Sci Inst, Smithsonian Astrophys Observ, NOAO AB With the realization of NASA's era of great observatories, there are now more than three space-based telescopes operating in different wave bands. This situation provides astronomers with a unique opportunity to simultaneously observe with multiple observatories. Yet scheduling multiple observatories simultaneously is highly inefficient when compared to observations using only a single observatory. Thus, programs using multiple observatories are limited not by scientific restrictions, but by operational inefficiencies. At present, multi-observatory programs are initiated by submitting observing proposals separately to each concerned observatory. To assure that the proposed observations can be scheduled, each observatory's staff has to check that the observations are valid and meet all constraints for their own observatory; in addition, they have to verify that the observations satisfy the constraints of the other observatories. Thus, coordinated observations require painstaking manual collaboration among staffs at each observatory. Due to the lack of automated tools for coordinated observations, this process is time consuming and error-prone, and the outcome of requests is not certain until the very end. To increase multi-observatory operations efficiency, such resource intensive processes need to be re-engineered. To overcome this critical deficiency, Goddard Space Flight Center's Advanced Architectures and Automation Branch is developing a prototype called the Visual Observation Layout Tool (VOLT). The main objective of VOLT is to provide visual tools to help automate the planning of coordinated observations by multiple astronomical observatories, as well as to increase the probability of scheduling all observations. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Jones, J (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-075-7 J9 ASTR SOC P PY 2001 VL 238 BP 44 EP 47 PG 4 WC Astronomy & Astrophysics; Computer Science, Software Engineering SC Astronomy & Astrophysics; Computer Science GA BU31S UT WOS:000175678400007 ER PT B AU Shopbell, PL Hsu, E Kadowaki, N Clark, G AF Shopbell, PL Hsu, E Kadowaki, N Clark, G BE Harnden, FR Primini, FA Payne, HE TI A Japan-US educational collaboration: Using the Telescopes In Education (TIE) program via intelsat SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS X SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 10th Annual Conference for Astronomical Data Analysis Software and Systems (ADASS 2000) CY NOV 12-15, 2000 CL BOSTON, MA SP Akibia Inc, Canada France Hawaii Telescope, NASA, Space Telescope Sci Inst, Smithsonian Astrophys Observ, NOAO AB In 1993, a proposal at the Japan-U.S. Science, Technology, and Space Applications Program (JUSTSAP) workshop lead to a series of satellite communications experiments and demonstrations, under the title of the Trans-Pacific High Data Rate Satellite Communications Experiments. These experiments were designed to explore and develop satellite communications techniques, standards, and protocols in order to determine how best to incorporate satellite links with fiber optic cables to form high performance global telecommunications networks. This paper describes a remote astronomy experiment executed during the second phase of this program, which established a ground- and space-based network between Japan and several sites in the U.S. This network was used by students, scientists, and educators to provide real-time interaction and collaboration with an automated 14-inch telescope and associated data archive. We find that such networking can provide educators and students with a unique collaborative environment which greatly enhances the educational experience. C1 CALTECH, JPL, Pasadena, CA 91125 USA. RP Shopbell, PL (reprint author), CALTECH, JPL, Pasadena, CA 91125 USA. NR 3 TC 0 Z9 0 U1 0 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-075-7 J9 ASTR SOC P PY 2001 VL 238 BP 115 EP 118 PG 4 WC Astronomy & Astrophysics; Computer Science, Software Engineering SC Astronomy & Astrophysics; Computer Science GA BU31S UT WOS:000175678400025 ER PT B AU Bambery, RJ Backus, C AF Bambery, RJ Backus, C BE Harnden, FR Primini, FA Payne, HE TI Prototypical operations support tools for NASA interferometer missions: Applications to studies of binary stars using the palomar testbed interferometer SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS X SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 10th Annual Conference for Astronomical Data Analysis Software and Systems (ADASS 2000) CY NOV 12-15, 2000 CL BOSTON, MA SP Akibia Inc, Canada France Hawaii Telescope, NASA, Space Telescope Sci Inst, Smithsonian Astrophys Observ, NOAO AB The Palomar Testbed Interferometer (PTI) is a 110-meter baseline K-Band infrared interferometer located at Palomar Mountain, California. In 1999 an effort was started to provide more observer-friendly observation planning and monitoring tools, such as might be used in NASA interferometer missions. This session illustrates how these prototype tools aid in the observation of spectroscopic binary stars. Animations, using IDL, show how the measured visibilities relate to the positions of the secondary star during its orbital period. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bambery, RJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-075-7 J9 ASTR SOC P PY 2001 VL 238 BP 369 EP 372 PG 4 WC Astronomy & Astrophysics; Computer Science, Software Engineering SC Astronomy & Astrophysics; Computer Science GA BU31S UT WOS:000175678400081 ER PT B AU Dorman, B Arnaud, K AF Dorman, B Arnaud, K BE Harnden, FR Primini, FA Payne, HE TI Redesign and reimplementation of XSPEC SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS X SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 10th Annual Conference for Astronomical Data Analysis Software and Systems (ADASS 2000) CY NOV 12-15, 2000 CL BOSTON, MA SP Akibia Inc, Canada France Hawaii Telescope, NASA, Space Telescope Sci Inst, Smithsonian Astrophys Observ, NOAO AB We present a progress report on the redesign of XSPEC. Work has been underway since late 1998 to produce a new version of XSPEC with a code base written in ANSI C++ and with modern design techniques. The new version (XSPEC 12) is expected to be ready for release in 2002. The new version of the program will implement most of the features of the current release, XSPEC 11. The design allows for both the current Tcl command line interface as well as an optional GUI. The existing scheme whereby users can write theoretical model components in FORTRAN 77 will, however, continue to be fully supported. Scientifically, the major change will be to support simultaneous fitting to spectral data containing multiple sources, required for coded mask instruments (such as Integral/SPI that are able, in principle, to separate superposed X-ray sources). The focus of the project is, however, to update the program to take advantages of the progress in programming technology that has been made in the field of Computer Science over the last 15 years since XSPEC was originally released. The main software engineering benefits of the redesign project are an extensible implementation that allows for (a) loosely coupled modules [providing ease of maintenance], including CCfits, a new ANSI C++ interface to the cfitsio library developed as a by-product; (b) extension of the supported data formats by 'add-in' user-loadable modules; (c) an independent user interface implementation; and (d) robustness guarantees such as exception safety. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Dorman, B (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 664, Greenbelt, MD 20771 USA. NR 2 TC 56 Z9 56 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-075-7 J9 ASTR SOC P PY 2001 VL 238 BP 415 EP 418 PG 4 WC Astronomy & Astrophysics; Computer Science, Software Engineering SC Astronomy & Astrophysics; Computer Science GA BU31S UT WOS:000175678400093 ER PT B AU Thomas, B Shaya, E Cheung, C AF Thomas, B Shaya, E Cheung, C BE Harnden, FR Primini, FA Payne, HE TI Converting FITS into XML: Methods and advantages SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS X SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 10th Annual Conference for Astronomical Data Analysis Software and Systems (ADASS 2000) CY NOV 12-15, 2000 CL BOSTON, MA SP Akibia Inc, Canada France Hawaii Telescope, NASA, Space Telescope Sci Inst, Smithsonian Astrophys Observ, NOAO AB We discuss how and why FITS data should be encapsulated in XML. Our goal is not to throw away the FITS standard entirely. Rather, we seek to re-map the FITS standard into an XML-based format. The advantages of doing so are legion and include: greater interoperability, parsing by XML aware browsers and applications, hierarchical structure for improved searchability, default values for header descriptions, extensibility for specialized usage and future development, and piggybacking on industry applications. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Thomas, B (reprint author), NASA, Goddard Space Flight Ctr, Code 631, Greenbelt, MD 20771 USA. NR 0 TC 4 Z9 5 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-075-7 J9 ASTR SOC P PY 2001 VL 238 BP 487 EP 490 PG 4 WC Astronomy & Astrophysics; Computer Science, Software Engineering SC Astronomy & Astrophysics; Computer Science GA BU31S UT WOS:000175678400111 ER PT J AU Poulet, F Sicardy, B AF Poulet, F Sicardy, B TI Astrometric observations of inner Saturnian satellites SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE planets and satellites : individual : Saturn; astrometry ID 8 MAJOR SATELLITES; RING-PLANE CROSSINGS; CCD ASTROMETRY; GENERAL-THEORY; NOVEMBER 1995; MOTION; ORBITS; AUGUST AB This paper presents observations of four inner Saturnian satellites (SX = Janus: SXI = Epimetheus. SXVI = Prometheus and SXVII = Pandora) made in August and November 1995 during the Earth and Sun crossings of Saturn's ring plane, respectively. The August 1995 data combine data taken with the Adonis: optics system mounted on the ESO 3.6-m telescope at La Silla, and images from the Hubble Space telescope (HST). The November 1995 data are based on HST images only. Orbits fits: show that these observations combined with those of Nicholson et al. (1996) have residuals of about 0.05 arcsec. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Observ Paris, Inst Univ France, F-92195 Meudon, France. RP Poulet, F (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. EM poulet@cosmic.arc.nasa.gov; sicardy@obspm.fr NR 18 TC 5 Z9 8 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 2001 VL 366 IS 1 BP 339 EP 342 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 404QQ UT WOS:000167112500036 ER PT J AU Barrow, CH Lecacheux, A MacDowall, RJ AF Barrow, CH Lecacheux, A MacDowall, RJ TI Jovicentric latitude effect on the bKOM radio emission observed by Ulysses/URAP SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE space vehicles; planets and satellites : Jupiter; radio continuum : solar system ID JUPITER; ENCOUNTER; VOYAGER; PLANETS AB During 1994 and into 1996, Ulysses was at distances of 5 AU or more from Jupiter and travelling from south to north of the ecliptic plane. At these distances, the jovian broadband radio emission (bKOM) was only received occasionally by the Unified Radio and Plasma Experiment (URAP) on board the Ulysses spacecraft. The signals were generally weak and much care is needed to find and to identify the events. It is found that the visibility and polarization of the bKOM appears to depend upon the jovicentric latitude of Ulysses (D-Uly) at the time of observation. All but two of the bKOM events observed when Ulysses was at northern jovicentric latitudes were predominantly right-hand (RH) polarized while events recorded when the spacecraft was at southerly jovicentric latitudes were all predominantly LH polarized. the change taking place somewhere between 3.9 degrees less than or equal to D-Uly less than or equal to 8.8 degrees, close to 0 degrees jovimagnetic latitude. Compared with previous observations of the bKOM, made by spacecraft considerably closer to Jupiter, the present occurrence probabilities were lower for the LH polarized events although the distribution was similar. For the RH polarized events, hoc-ever, the distribution was different, the so-called main peak being absent or, perhaps, displaced towards a larger central meridian longitude. It is shown that, in a two-dimensional model, if cyclotron maser emission in a dipole magnetic field is assumed for Jupiter, the detection of bKOM at a given frequency by a spacecraft at a specified location, determines a unique value of beta for an assumed value of L and a given field model. This is not true for a three-dimensional model. The present results raise questions on the application of the cyclotron maser theory to bKOM emission. C1 Max Planck Inst Aeron, D-37189 Katlenburg Lindau, Germany. Observ Paris, ARPEGES, F-92195 Meudon, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Barrow, CH (reprint author), Max Planck Inst Aeron, D-37189 Katlenburg Lindau, Germany. EM barrow@linmpi.mpg.de RI MacDowall, Robert/D-2773-2012 NR 23 TC 2 Z9 2 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 2001 VL 366 IS 1 BP 343 EP 350 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 404QQ UT WOS:000167112500037 ER PT J AU Contursi, A Boselli, A Gavazzi, G Bertagna, E Tuffs, R Lequeux, J AF Contursi, A Boselli, A Gavazzi, G Bertagna, E Tuffs, R Lequeux, J TI Mid and Far IR properties of late-type galaxies in the Coma and A1367 clusters: ISOCAM and ISOPHOT observations SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : cluster : Coma; A 1367; galaxies : ISM; galaxies : irregular; galaxies : spiral; infrared : galaxies ID SPIRAL GALAXIES; INTERSTELLAR DUST; STAR-FORMATION; INFRARED-EMISSION; ULTRAVIOLET OBSERVATIONS; NEARBY CLUSTERS; H-ALPHA; ANDROMEDA GALAXY; VIRGO CLUSTER; DISK GALAXIES AB We present Mid (MIR) and Far (FIR) Infrared observations of 18 spiral/irregular galaxies belonging to the Coma and A1367 clusters, carried out with the CAM and PHOT instruments on board the ISO satellite. Complementary photometry from the UV to the Near Infrared (NIR) together with H alpha imaging, HI and (CO)-C-12 line measurements allow us to study the relationships between the IR emission and the star formation properties of these galaxies. Most of the resolved galaxies show extended MIR emission throughout their disks even where no H alpha emission is present. This suggests that the Aromatic carriers can be excited by the general interstellar radiation field (ISRF), i.e. by visible photons. Only close to HII regions the UV photons are the principal sources of Aromatic carrier excitation. However, when the UV radiation field becomes intense enough these carriers can be destroyed. The average integrated 15/6.75 HII ratio of the observed galaxies is similar to1, i.e. the typical value for the photodissociation regions (PDRs). This suggests that, despite the high star formation rate (SFR) and the very luminous HII regions of these galaxies, their integrated MIR emission is dominated by PDR-like regions rather than HII-like regions. A cold dust component with average temperature similar to 22 K exists in most of the target galaxies, probably arising from big dust grains (BGs) in thermal equilibrium with the ISRF. The contribution to the BGs heating from the ionizing stars decreases with increasing wavelength. A warmer dust component whose emission dominates the spectrum between 20 and 100 mum is likely to exist. This is probably due to both Very Small Grains (VSGs) and warm BGs emission. The dust to gas ratio of the target galaxies is comparable to that of the solar neighborhood. There is a weak trend between the dust total mass and both the atomic and molecular gas content. The MIR and FIR properties of the analyzed galaxies do not seem to be affected by the environment despite the fact that most of the targets are interacting with the Intra-Cluster-Medium. C1 Observ Paris, DEMIRM, F-75014 Paris, France. Ctr Etud Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. CALTECH, Jet Prop Lab, IPAC, Pasadena, CA 91125 USA. Astron Spatiale Lab, F-13376 Marseille, France. Univ Milan, I-20126 Milan, Italy. Max Planck Inst Kernphys, D-69117 Heidelberg, Germany. RP Contursi, A (reprint author), Observ Paris, DEMIRM, 61 Av Observ, F-75014 Paris, France. EM contursi@ipac.caltech.edu NR 68 TC 32 Z9 32 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 2001 VL 365 IS 2 BP 11 EP 27 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 394UF UT WOS:000166541100002 ER PT J AU Eiroa, C Garzon, F Alberdi, A de Winter, D Ferlet, R Grady, CA Cameron, A Davies, JK Deeg, HJ Harris, AW Horne, K Merin, B Miranda, LF Montesinos, B Mora, A Oudmaijer, R Palacios, J Penny, A Quirrenbach, A Rauer, H Schneider, J Solano, E Tsapras, Y Wesselius, PR AF Eiroa, C Garzon, F Alberdi, A de Winter, D Ferlet, R Grady, CA Cameron, A Davies, JK Deeg, HJ Harris, AW Horne, K Merin, B Miranda, LF Montesinos, B Mora, A Oudmaijer, R Palacios, J Penny, A Quirrenbach, A Rauer, H Schneider, J Solano, E Tsapras, Y Wesselius, PR TI EXPORT: Near-IR observations of Vega-type and pre-main sequence stars SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : emission-line, Be; stars : pre-main sequence; stars : variable : general; infrared : stars ID YOUNG STELLAR OBJECTS; HERBIG AE/BE STARS; BETA-PICTORIS; CIRCUMSTELLAR DISK; SYSTEM; SEARCH; DUST; AGE AB We present near-IR JHK photometric data of a sample of 58 main-sequence, mainly Vega-type, and pre-main sequence stars. The data were taken during four observing runs ill the period May 1998 to January 1999 and form part of a coordinated effort with simultaneous optical spectroscopy and photo-polarimetry. The near-IR colors of the MS stars correspond in most cases to photospheric colors, although noticeable reddening is present towards a fen objects, and these stars show no brightness variability within the observational errors. On the other hand, the PMS stars show near-IR excesses and variability consistent with previous data. C1 Univ Autonoma Madrid, Fac Ciencias, Dept Fis Teor, E-28049 Madrid, Spain. Inst Astrofis Canarias, E-38200 La Laguna, Tenerife, Spain. Inst Astrofis Andalucia, E-18080 Granada, Spain. TNO, TPD Space Instrumentat, NL-2600 AD Delft, Netherlands. CNRS, Inst Astrophys, F-75014 Paris, France. NASA, Goddard Space Flight Ctr, NOAO, STIS, Greenbelt, MD 20771 USA. Univ St Andrews, St Andrews KY16 9SS, Fife, Scotland. Joint Astron Ctr, Hilo, HI 96720 USA. DLR, Dept Planetary Explorat, D-12489 Berlin, Germany. VILSPA, LAEFF, Madrid 28080, Spain. Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Univ Calif San Diego, Ctr Astrophys & Space Sci, Dept Phys, La Jolla, CA 92093 USA. Observ Paris, F-92195 Meudon, France. Univ Complex Zernike, SRON, NL-9700 AV Groningen, Netherlands. RP Eiroa, C (reprint author), Univ Autonoma Madrid, Fac Ciencias, Dept Fis Teor, E-28049 Madrid, Spain. EM carlos@xiada.ft.uam.es RI Solano, Enrique/C-2895-2017; Montesinos, Benjamin/C-3493-2017; OI Montesinos, Benjamin/0000-0002-7982-2095; Cameron, Andrew/0000-0002-8863-7828; Deeg, Hans-Jorg/0000-0003-0047-4241; Merin, Bruno/0000-0002-8555-3012 NR 37 TC 38 Z9 38 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 2001 VL 365 IS 2 BP 110 EP 114 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 394UF UT WOS:000166541100008 ER PT J AU Bautista, MA AF Bautista, MA TI Atomic data from the iron project XLVII. Electron impact excitation of NiIII SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE atomic data; line : formation; ISM : abundances; ultraviolet : general ID ORION NEBULA; CRAB-NEBULA; CROSS-SECTIONS; SPECTROPHOTOMETRY; LINES AB This paper reports R-matrix calculations of electron impact excitation rates for Ni III. The calculation includes 70 LS terms corresponding to the configurations 3d(8), 3d(7)4s, 3d(7) 4p, and 3d(6)4s(2). This expansion results in 162 fine structure levels and 13 041 transitions, including optical, infrared, and ultraviolet lines. The collision strengths, including detailed resonance structures, were integrated over a Maxwellian distribution of electron enemies and the resulting effective collision strengths are given for a wide range of temperatures. A collisional-radiative equilibrium model of the Ni III ion is constructed and the strongest. lines in the optical and infrared spectral regions are identified. The emissivities of these lines and emissivity line ratio diagnostics are presented. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Bautista, MA (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 662, Greenbelt, MD 20771 USA. EM bautista@lhea1.gsfc.nasa.gov NR 22 TC 13 Z9 13 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 2001 VL 365 IS 2 BP 268 EP 274 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 394UF UT WOS:000166541100027 ER PT J AU Moy, E Rocca-Volmerange, B Fioc, M AF Moy, E Rocca-Volmerange, B Fioc, M TI Evolution of photoionization and star formation in starbursts and H (II) galaxies SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : starburst; galaxies : evolution; galaxies : stellar content; ISM : HII regions ID COMBINED STELLAR STRUCTURE; HUBBLE DEEP FIELD; RADIATIVE OPACITIES; ATMOSPHERE MODELS; MASSIVE STARS; HII-REGIONS; REDSHIFTS Z-GREATER-THAN-3; THEORETICAL-MODELS; SPECTRAL-SYNTHESIS; NUCLEUS GALAXIES AB We analyze coherently the stellar and nebular energy distributions of starbursts and H II galaxies, using our evolutionary synthesis model, PEGASE (Fioc & Rocca-Volmerange 1997, 2000), coupled to the photoionization code CLOUDY (Ferland 1996). The originality of this study is to relate the evolution and the metallicity of the starburst to the past star formation history of the host galaxy Extinction and geometrical effects on emission lines and continua are computed in coherency with metallicity. We compare our model predictions to an observed sample of approximate to M750 H II regions and starbursts. When fitting [O III](lambda 4363)/[O III]lambda (5007), [O I](lambda 6300)/H alpha, [S II](lambda lambda 6716,6731)/H alpha, [N II](lambda 6584)/H alpha and [O III](lambda 5007)/H beta, the most striking feature is the decreasing spread in U with increasing metallicity Z. High-U objects systematically have a low metallicity while low levels of excitation happen at any Z. The best fits of emission line ratios are obtained with a combination of a high- and a low-ionization components. No additional source of ionizing photons - shocks or hidden AGN - is needed. The high level of excitation observed in metal-poor H II galaxies requires a very young population (less than or equal to 3 Myr), while starburst nuclear galaxies (SBNGs) are consistent with a wider range of age (less than or equal to 5 Myr). Colors (B - V, V - R) and equivalent widths are fitted in coherency with emission line ratios. An underlying population is needed, even for small-aperture observations. This underlying population not only reddens the continuum and dilutes the equivalent width of the emission lines, but also participates in the ionization process. Its main effect on line ratios is to maintain a high level of excitation when the burst stops. Models combining underlying populations typical of Hubble sequence galaxies and instantaneous starbursts with ages between 0 and 8 Myr agree satisfactorily with all the data. C1 Inst Astrophys, F-75014 Paris, France. Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Inst Astrophys, 98 Bis Blvd Arago, F-75014 Paris, France. EM moy@iap.fr NR 75 TC 45 Z9 45 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 2001 VL 365 IS 3 BP 347 EP 359 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 402PV UT WOS:000166998100002 ER PT J AU Belsole, E Sauvageot, JL Bohringer, H Worrall, DM Matsushita, K Mushotzky, RF Sakelliou, I Molendi, S Ehle, M Kennea, J Stewart, G Vestrand, WT AF Belsole, E Sauvageot, JL Bohringer, H Worrall, DM Matsushita, K Mushotzky, RF Sakelliou, I Molendi, S Ehle, M Kennea, J Stewart, G Vestrand, WT TI An XMM-Newton study of the sub-structure in M 87's halo SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : clusters : individual : Virgo; galaxies : individual : M 87; radio continuum : galaxies; radio galaxies : individual : 3C 274; X-rays : galaxies ID PHOTON IMAGING CAMERA; VIRGO CLUSTER; RADIO HALO; M87; GALAXIES; DISTANCE; MASS; GAS AB The high signal to noise and good point spread function of XMM have allowed the first detailed study of the interaction between the thermal and radio emitting plasma in the central regions of M 87. We show that the X-ray emitting structure, previously seen by ROSAT, is thermal in nature and that the east and southwest extensions in M 87's X-ray; halo have a significantly lower temperature (kT = 1.5 keV) than the surrounding ambient medium (kT = 2.3 keV). There is little or no evidence for non-thermal emission with an upper limit on the contribution of a power law component of spectral index flatter than 3 being less than 1% of the flux iu the region of the radio lobes. C1 CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. Univ Bristol, Dept Phys, Bristol BS8 1TL, Avon, England. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Ist Fis Cosmica, I-20133 Milan, Italy. XMM Newton SOC, Madrid 28080, Spain. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Los Alamos Natl Lab, NIS2, Los Alamos, NM 87545 USA. RP CEA Saclay, Serv Astrophys, Orme Merisiers,Bat 709, F-91191 Gif Sur Yvette, France. EM ebelsole@cea.fr NR 26 TC 60 Z9 60 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 2001 VL 365 IS 1 BP L188 EP L194 DI 10.1051/0004-6361:20000239 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 392RV UT WOS:000166426300030 ER PT J AU Bohringer, H Belsole, E Kennea, J Matsushita, K Molendi, S Worrall, DM Mushotzky, RF Ehle, M Guainazzi, M Sakelliou, I Stewart, G Vestrand, WT Dos Santos, S AF Bohringer, H Belsole, E Kennea, J Matsushita, K Molendi, S Worrall, DM Mushotzky, RF Ehle, M Guainazzi, M Sakelliou, I Stewart, G Vestrand, WT Dos Santos, S TI XMM-Newton observations of M 87 and its X-ray halo SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : individual : M 87; galaxies : clusters : individual : Virgo; X-rays : galaxies; galaxies : active ID PHOTON IMAGING CAMERA; HIGH-RESOLUTION; VIRGO CLUSTER; M87 JET; NUCLEUS; RADIO; BRIGHTNESS; TELESCOPE; GALAXIES; EMISSION AB We report performance verification observations of the giant elliptical galaxy M 87 in the Virgo Cluster with the MOS, pn, and optical monitor instruments on board of XMM-Newton. With the energy sensitive imaging instruments MOS and pn we obtain the first spatially constrained X-ray spectra of the nucleus and the jet of the galaxy. The good photon statistics of the pn and MOS allow a detailed analysis of the radial temperature and abundance distribution of 6 elements. The data provide no indication of a multi-temperature structure for radii greater than or equal to2'. An apparent sharp metal abundance drop deduced for the regions inside this radius is probably due to resonant line scattering. C1 Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Ist Fis Cosmica, I-20133 Milan, Italy. Univ Bristol, Dept Phys, Bristol BS8 1TL, Avon, England. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. ESA, XMM Newton SOC, VILSPA, Madrid 28080, Spain. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Los Alamos Natl Lab, NIS2, Los Alamos, NM 87545 USA. RP Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. OI Molendi, Silvano/0000-0002-2483-278X NR 35 TC 133 Z9 133 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 2001 VL 365 IS 1 BP L181 EP L187 DI 10.1051/0004-6361:20000092 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 392RV UT WOS:000166426300029 ER PT J AU Mittaz, JPD Kaastra, JS Tamura, T Fabian, AC Mushotzky, RF Peterson, JR Ikebe, Y Lumb, DH Paerels, F Stewart, G Trudolyubov, S AF Mittaz, JPD Kaastra, JS Tamura, T Fabian, AC Mushotzky, RF Peterson, JR Ikebe, Y Lumb, DH Paerels, F Stewart, G Trudolyubov, S TI UV observations of the galaxy cluster Abell 1795 with the optical monitor on XMM-Newton SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : clusters : individual Abell 1795; galaxies : stellar content; ultraviolet : galaxies ID RAY LUMINOUS CLUSTERS; COOLING FLOWS; EMISSION; SPECTROSCOPY; CORES; DUST; GAS AB We present the results of an analysis of broad band UV observations of the central regions of Abell 1795 observed with the optical monitor on XMM-Newton. As have been found with other UV observations of the central regions of clusters of galaxies, we find evidence for star formation. However, we also find evidence for absorption in the cD galaxy on a more extended scale than has been seen with optical imaging. We also report the first UV observation of part of the filamentary structure seen in H alpha, X-rays and very deep U band imaging. The part of the filament we see is very blue with UV colours consistent with a very early (O/B) stellar population. This is the first direct evidence of a dominant population of early type stars at the centre of Abell 1795 and implies very recent star formation at the centre of this cluster. C1 UCL, Mullard Space Sci Lab, Dept Space & Climate Phys, Surrey, England. SRON, Space Res Lab, NL-3584 CA Utrecht, Netherlands. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Columbia Univ, Dept Phys, New York, NY 10027 USA. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. European Space Agcy, ESTEC, Div Astrophys, NL-2200 AG Noordwijk, Netherlands. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Mittaz, JPD (reprint author), UCL, Mullard Space Sci Lab, Dept Space & Climate Phys, Surrey, England. RI Tamura, Takayuki/K-8236-2012 NR 24 TC 23 Z9 23 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 2001 VL 365 IS 1 BP L93 EP L98 DI 10.1051/0004-6361:20000019 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 392RV UT WOS:000166426300014 ER PT J AU Page, MJ Mason, KO Carrera, FJ Clavel, J Kaastra, JS Puchnarewicz, EM Santos-Lleo, M Brunner, H Ferrigno, C George, IM Paerels, F Pounds, KA Trudolyubov, SP AF Page, MJ Mason, KO Carrera, FJ Clavel, J Kaastra, JS Puchnarewicz, EM Santos-Lleo, M Brunner, H Ferrigno, C George, IM Paerels, F Pounds, KA Trudolyubov, SP TI The variable XMM-Newton spectrum of Markarian 766 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE accretion, accretion disks; black hole physics; galaxies : Seyfert; X-rays : general ID ACTIVE GALACTIC NUCLEI; SEYFERT 1 GALAXIES; X-RAY-EMISSION; ACCRETION DISK; BLACK-HOLE; VARIABILITY; MCG-6-30-15; LINES AB The narrow-line Seyfert 1 galaxy Mrk 766 was observed for GO ks with the XMM-Newton observatory. The source shows a complex X-ray spectrum. The 2-10 keV spectrum can be adequately represented by a power law and broad Fe Ka emission. Between 0.7 and 2 keV the spectrum is harder and exhibits a flux deficit with respect to the extrapolated medium energy slope. Below 0.7 keV, however, there is a strong excess of emission. The RGS spectrum shows an edge-like feature at 0.7 keV; the energy of this feature is inconsistent with that expected for an OVII edge from a warm absorber, Mrk 766 varies by a factor of similar to2 in overall count rate in the EPIC and RGS instruments on a timescale of a few thousand seconds, while no significant flux changes are observed in the ultraviolet with the Oh I. The X-ray variability is spectrally dependent with the largest amplitude variability occurring ill the 0.4-2 keV band. The spectral variability can be explained by a change in flux and slope of the medium energy continuum emission, superimposed on a less variable (or constant) low energy emission component. C1 UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Univ Cantabria, Inst Fis Cantabria, CSIC, E-39005 Santander, Spain. ESA, XMM Newton Sci Operat Ctr, Div Astrophys, Dept Space Sci, Madrid 28080, Spain. SRON, Space Res Lab, NL-3584 CA Utrecht, Netherlands. Astrophys Inst Potsdam, D-14482 Potsdam, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Leicester, Dept Phys & Astron, Xray Astron Grp, Leicester LE1 7RH, Leics, England. Los Alamos Natl Lab, NIS2, Los Alamos, NM 87545 USA. RP Page, MJ (reprint author), UCL, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England. EM mjp@mssl.ucl.ac.uk RI Ferrigno, Carlo/H-4139-2012 NR 17 TC 25 Z9 26 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 2001 VL 365 IS 1 BP L152 EP L157 DI 10.1051/0004-6361:20000240 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 392RV UT WOS:000166426300024 ER PT J AU Peterson, JR Paerels, FBS Kaastra, JS Arnaud, M Reiprich, TH Fabian, AC Mushotzky, RF Jernigan, JG Sakelliou, I AF Peterson, JR Paerels, FBS Kaastra, JS Arnaud, M Reiprich, TH Fabian, AC Mushotzky, RF Jernigan, JG Sakelliou, I TI X-ray imaging-spectroscopy of Abell 1835 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxy clusters : individual : Abell 1835; galaxies : cooling flows; techniques : spectroscopic ID CLUSTER COOLING FLOWS; THERMAL CONDUCTION; MAGNETIC-FIELDS; EMISSION-LINE; GALAXIES; ASCA; GAS AB We present detailed spatially-resolved spectroscopy results of the observation of Abell 1835 using the European Photon Imaging Cameras (EPIC) and the Reflection Grating Spectrometers (RGS) on the XMM-Newton observatory. Abell 1835 is a luminous (10(46) ergs s(-1)), medium redshift (z = 0.2523), X-ray emitting cluster of galaxies. The observations support the interpretation that large amounts of cool gas are present in a multi-phase medium surrounded by a hot (kT(e) = 8.2 keV) outer envelope. We detect O VIII Ly alpha and two Fe XXIV complexes in the RGS spectrum. The emission measure of the cool gas below kT(e) = 2.7 keV is much lower than expected from standard cooling-flow models, suggesting either a more complicated cooling process than simple isobaric radiative cooling or differential cold absorption of the cooler gas. C1 Columbia Dept Phys, New York, NY 10027 USA. Astrophys Lab, New York, NY 10027 USA. SRON, Space Res Lab, NL-3584 CA Utrecht, Netherlands. CEA, DSM, DAPNIA, Serv Astrophys, F-91191 Gif Sur Yvette, France. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. Astron Inst, Cambridge CB3 OHA, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. UCL, Mullard Space Sci Lab, Surrey RH5 6NT, England. RP Columbia Dept Phys, 550 W 120th St, New York, NY 10027 USA. EM jrpeters@astro.columbia.edu NR 37 TC 259 Z9 260 U1 1 U2 3 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 2001 VL 365 IS 1 BP L104 EP L109 DI 10.1051/0004-6361:20000021 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 392RV UT WOS:000166426300016 ER PT J AU Tamura, T Kaastra, JS Peterson, JR Paerels, FBS Mittaz, JPD Trudolyubov, SP Stewart, G Fabian, AC Mushotzky, RF Lumb, DH Ikebe, Y AF Tamura, T Kaastra, JS Peterson, JR Paerels, FBS Mittaz, JPD Trudolyubov, SP Stewart, G Fabian, AC Mushotzky, RF Lumb, DH Ikebe, Y TI X-ray spectroscopy of the cluster of galaxies Abell 1795 with XMM-Newton SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : clusters : individual : Abell 1795; galaxies : clusters : general; galaxies : cooling flows; X-rays : galaxies ID COOLING FLOWS; CENTRAL REGION; ABUNDANCES; DISCOVERY; SOLAR AB The initial results from XMM-Newton observations of the rich cluster of galaxies Abell 1795 are presented. The spatially-resolved X-ray spectra taken by the European Photon Imaging Cameras (EPIC) show a temperature drop at a radius of similar to 200 kpc from the cluster center, indicating that the ICM is cooling. Both the EPIC and the Reflection Grating Spectrometers (RGS) spectra extracted from the cluster center can be described by an isothermal model with a temperature of similar to4 keV. The volume emission measure of any cool component (< 1 keV) is less than a few % of the hot component at the cluster center. A strong O-VIII Lyman line was detected with the RGS from the cluster core. The O abundance and its ratio to Fe at the cluster center is 0.2-0,5 and 0.5-1.5 times the solar value, respectively. C1 SRON, Space Res Lab, NL-3584 CA Utrecht, Netherlands. Columbia Univ, Astrophys Lab, New York, NY 10027 USA. UCL, Mullard Space Sci Lab, Dept Space & Climate Phys, Surrey, England. Los Alamos Natl Lab, NIS 2, Los Alamos, NM 87545 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1, Leics, England. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. European Space Agcy, ESTEC, Div Astrophys, NL-2200 AG Noordwijk, Netherlands. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. RP SRON, Space Res Lab, Sorbonnelaan 2, NL-3584 CA Utrecht, Netherlands. EM T.Tamura@sron.nl RI Tamura, Takayuki/K-8236-2012 NR 26 TC 230 Z9 232 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 2001 VL 365 IS 1 BP L87 EP L92 DI 10.1051/0004-6361:20000038 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 392RV UT WOS:000166426300013 ER PT J AU Watson, MG Augueres, JL Ballet, J Barcons, X Barret, D Boer, M Boller, T Bromage, GE Brunner, H Carrera, FJ Cropper, MS Denby, M Ehle, M Elvis, M Fabian, AC Freyberg, MJ Guillout, P Hameury, JM Hasinger, G Hinshaw, DA Maccacaro, T Mason, KO McMahon, RG Michel, L Mirioni, L Mittaz, JP Motch, C Olive, JF Osborne, JP Page, CG Pakull, M Perry, BH Pierre, M Pietsch, W Pye, JP Read, AM Roberts, TP Rosen, SR Sauvageot, JL Schwope, AD Sekiguchi, K Stewart, GC Stewart, I Valtchanov, I Ward, MJ Warwick, RS West, RG White, NE Worrall, DM AF Watson, MG Augueres, JL Ballet, J Barcons, X Barret, D Boer, M Boller, T Bromage, GE Brunner, H Carrera, FJ Cropper, MS Denby, M Ehle, M Elvis, M Fabian, AC Freyberg, MJ Guillout, P Hameury, JM Hasinger, G Hinshaw, DA Maccacaro, T Mason, KO McMahon, RG Michel, L Mirioni, L Mittaz, JP Motch, C Olive, JF Osborne, JP Page, CG Pakull, M Perry, BH Pierre, M Pietsch, W Pye, JP Read, AM Roberts, TP Rosen, SR Sauvageot, JL Schwope, AD Sekiguchi, K Stewart, GC Stewart, I Valtchanov, I Ward, MJ Warwick, RS West, RG White, NE Worrall, DM TI The XMM-Newton serendipitous survey I. The role of XMM-Newton Survey Science Centre SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE surveys; methods : data analysis; X-rays : general; X-rays : galaxies; X-rays : stars ID MEDIUM-SENSITIVITY SURVEY; PHOTON IMAGING CAMERA; ROSAT DEEP SURVEY; X-RAY SOURCES; LOCKMAN-HOLE AB This paper describes the performance of XMM-Newton for serendipitous surveys and summarises the scope and potential of the XMM-Newton Serendipitous Survey. The role of the Survey Science Centre (SSC) in the XMM-Newton project is outlined. The SSC's follow-up and identification programme for the XMM-Newton serendipitous survey is described together with the presentation of some of the first results. C1 Univ Leicester, Dept Phys & Astron, Xray AStron Grp, Leicester LE1 7RH, Leics, England. CEA Saclay, DSM, DAPNIA, SAp, F-91191 Gif Sur Yvette, France. UC, CSIC, Inst Fis Cantabria, Santander 39005, Spain. Ctr Etud Spatiale Rayonnements, F-31028 Toulouse, France. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. Univ Cent Lancashire, Ctr Astrophys, Preston PR1 2HE, Lancs, England. Astrophys Inst Potsdam, D-14482 Potsdam, Germany. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Observ Astron, F-67000 Strasbourg, France. Osserv Astron Brera, I-20121 Milan, Italy. Subaru Telescope, NAOJ, Hilo, HI 96720 USA. NASA, Goddard Space Flight Ctr, LHEA, Greenbelt, MD 20771 USA. Univ Bristol, Dept Phys, Bristol BS8 1TL, Avon, England. XMM Newton SOC, Madrid 28080, Spain. RP Univ Leicester, Dept Phys & Astron, Xray AStron Grp, Leicester LE1 7RH, Leics, England. RI White, Nicholas/B-6428-2012; Barcons, Xavier/L-3335-2014; OI White, Nicholas/0000-0003-3853-3462; Barcons, Xavier/0000-0003-1081-8861; McMahon, Richard/0000-0001-8447-8869; Hameury, Jean-Marie/0000-0002-6412-0103; Boer, Michel/0000-0001-9157-4349 NR 13 TC 94 Z9 94 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 2001 VL 365 IS 1 BP L51 EP L59 DI 10.1051/0004-6361:20000067 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 392RV UT WOS:000166426300008 ER PT J AU Scoccimarro, RN Sheth, RK Hui, L Jain, B AF Scoccimarro, RN Sheth, RK Hui, L Jain, B TI How many galaxies fit in a halo? Constraints on galaxy formation efficiency from spatial clustering SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; galaxies : clusters : general; large-scale structure of universe ID LARGE-SCALE STRUCTURE; COSMOLOGICAL PERTURBATION-THEORY; 3-POINT CORRELATION-FUNCTION; GAUSSIAN INITIAL CONDITIONS; DARK-MATTER HALOES; HIERARCHICAL UNIVERSE; SKEWNESS; BIAS; CONDENSATION; STATISTICS AB We study galaxy clustering in the framework of halo models, where gravitational clustering is described in terms of dark matter halos. At small scales, dark matter clustering statistics are dominated by halo density profiles, whereas at large scales, correlations are the result of combining nonlinear perturbation theory with halo biasing. Galaxies are assumed to follow the dark matter profiles of the halo they inhabit, and galaxy formation efficiency is characterized by the number of galaxies that populate a halo of given mass. This approach leads to generic predictions : the galaxy power spectrum shows a power-law behavior even though the dark matter does not, and the galaxy higher order correlations show smaller amplitudes at small scales than their dark matter counterparts. Both are in qualitatively agreement with measurements in galaxy catalogs. We find that requiring the model to fit both the second- and third-order moments of the Automatic Plate Measuring Facility (APM) galaxies provides a strong constraint on galaxy formation models. The data at large scales require that galaxy formation be relatively efficient at small masses, m approximate to 10(10) M-. h(-1), whereas data at smaller scales require that the number of galaxies in a halo scale approximately as the mass to the 0.8th power in the high-mass limit. These constraints are independent of those derived from the luminosity function or Tully-Fisher relation. We also predict the power spectrum, bispectrum, and higher order moments of the mass density field in this framework. Although halo models agree well with measurements of the mass power spectrum and the higher order S-p parameters in N-body simulations, the model assumption that halos are spherical leads to disagreement in the configuration dependence of the bispectrum at small scales. We stress the importance of finite-volume effects in higher order statistics and show how they can be estimated in this approach. C1 Inst Adv Study, Sch Nat Sci, Princeton, NJ 08540 USA. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Johns Hopkins Univ, Dept Phys, Baltimore, MD 21218 USA. RP Scoccimarro, RN (reprint author), Inst Adv Study, Sch Nat Sci, Einstein Dr, Princeton, NJ 08540 USA. NR 65 TC 408 Z9 410 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2001 VL 546 IS 1 BP 20 EP 34 DI 10.1086/318261 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 390DL UT WOS:000166280400002 ER PT J AU Tingay, SJ Murphy, DW AF Tingay, SJ Murphy, DW TI Estimates of the free-free optical depth toward the subparsec-scale radio source in Centaurus A SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (Centaurus A); galaxies : jets; radiation mechanisms : thermal; radio continuum : galaxies; techniques : interferometric AB Multifrequency, near-simultaneous VLBA observations have been used to achieve matched resolution images of the inner 8 pc of Centaurus A, including the jet, the nucleus, and the counterjet, at a spatial resolution of approximately 0.1 pc. By comparing the three images, at 2.2, 5.0, and 8.4 GHz, and assuming a constant intrinsic spectral index between 2.2 and 8.4 GHz along each line of sight, it is possible, in principle, to separate the effects of synchrotron self-absorption intrinsic to the radio source from free-free absorption, which is extrinsic. Toward the unresolved Centaurus A nucleus, the observed spectral index between 2.2 and 5.0 GHz is inverted to an extent where free-free absorption is unavoidable, alpha = 3.8 +/- (0.6)(0.5), at its peak. Toward this region the optical depth to free-free absorption is estimated to be tau (ff) = 0.90 +/- 0.4 at 2.2 GHz, giving an intrinsic spectral index of alpha = 2.0 +/- 0.5, within the bounds explainable by synchrotron self-absorption. Away from the nucleus the remainder of the bright subparsec-scale radio jet has a spectral index close to -0.7 and is not affected by free-free absorption. We adopt a simple spherical geometry for the nuclear absorber with an upper limit on its radius of 0.016 pc, giving a constraint on the electron density and temperature, where is the electron density in units of 10(4) cm(-3) and T-4 is the electron temperature in units of 10(4) K. Assuming T-4 = 1 gives a lower limit for the total mass of the absorber of 0.01 M.. Future observations of higher resolution and sensitivity will be required to more accurately constrain the properties of the nuclear absorber and detect any absorption toward the counterjet. C1 CSIRO, Australia Telescope Natl Facil, Paul Wild Observ, Narrabri, NSW 2390, Australia. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tingay, SJ (reprint author), CSIRO, Australia Telescope Natl Facil, Paul Wild Observ, Locked Bag 194, Narrabri, NSW 2390, Australia. RI Tingay, Steven/B-5271-2013 NR 17 TC 27 Z9 27 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2001 VL 546 IS 1 BP 210 EP 215 DI 10.1086/318247 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 390DL UT WOS:000166280400018 ER PT J AU Amari, S Nittler, LR Zinner, E Gallino, R Lugaro, M Lewis, RS AF Amari, S Nittler, LR Zinner, E Gallino, R Lugaro, M Lewis, RS TI Presolar SiC grains of type Y: Origin from low-metallicity asymptotic giant branch stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust; extinction; Galaxy : evolution; ISM : abundances; nuclear reactions, nucleosynthesis, abundances stars : AGB and post-AGB ID SILICON-CARBIDE GRAINS; CARBON-ISOTOPE RATIOS; GALACTIC CHEMICAL EVOLUTION; SOLAR-SYSTEM FORMATION; S-PROCESS BA; MURCHISON METEORITE; STELLAR NUCLEOSYNTHESIS; INTERSTELLAR GRAINS; MASSIVE STARS; RED GIANTS AB We report isotopic data for 27 presolar SiC grains of the rare subtype Y in an acid-resistant residue of the Murchison (CM2) meteorite. Presolar SiC grains of type Y constitute only similar to1% of Murchison SiC grains larger than similar to2 km and are defined as having (12)C/(13)C > 100 (solar = 89) and (14)N/(15)N > 272 (solar). In a Si 3-isotope plot, their Si isotopic compositions plot to the right of the correlation line defined by the majority of presolar SiC grains (the mainstream population), whose isotopic compositions indicate an origin in C-rich asymptotic giant branch (AGB) stars of near-solar metallicity. Because of their low abundance, the new Y grains were identified by automatic isotopic imaging of the (12)C/(13)C ratio in the ion microprobe. We report C, N, and Si isotopic ratios of all 27 grains, inferred initial (26)Al/(27)Al ratios of 18, and Ti isotopic ratios of 20 grains. Whereas (14)N/(15)N and (26)Al/(27)Al ratios exhibit the same range as mainstream grains, the C, Si, and Ti isotopic ratios are distinct. Carbon-12/carbon-13 ratios range up to 295 and (30)Si/(28)Si excesses up to 183 parts per thousand relative to solar. The average (29)Si/(28)Si ratio of Y grains is by smaller than that of mainstream grains. Ti isotopic ratios relative to (48)Ti are somewhat similar to those of mainstream grains, but extend to more extreme anomalous compositions. One grain has (46)Ti/(48)Ti, (49)Ti/(48)Ti, and (50)Ti/(48)Ti excesses of and respectively, relative to 183 parts per thousand, 365 parts per thousand, 990 parts per thousand, solar. These features exhibited by Y grains point to an origin in AGB stars of somewhat lower than solar metallicity. In the envelope of such stars the proportion of (12)C and s-processed material dredged up from deep zones that experienced partial He burning and was mixed with original material is higher than in stars of solar metallicity. Their envelopes are therefore expected to have larger (12)C/(13)C, (30)Si/(28)Si, and (49)Ti/(48)Ti and (50)Ti/(48)Ti ratios than mainstream grains. We compare the C, Si, and Ti isotopic compositions of Y grains with the results of theoretical models of AGB stars with 1.5, 3, and 5 and M. and Z = 0.006, 0.01, and 0.02. While solar-metallicity (Z = 0.02) AGB models cannot account for the Y grain data, the models with Z = 0.01 can reproduce the measured isotopic compositions reasonably well. A range of stellar masses (from 1.5 M. possibly up to 5 M.) is indicated by the grain data. The present study together with additional data on SiC grains of type Z furthermore indicate that the rate of change of the ratios of the secondary Si isotopes ((29)Si and (30)Si) relative to (28)Si prior to solar system formation was lower than has been generally assumed, implying larger contributions of (28)Si from Type Ia supernovae compared to those from Type II supernovae. The Si isotopic ratios of Galactic cosmic rays also suggest such an evolution. C1 Washington Univ, Space Sci Lab, St Louis, MO 63130 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. Univ Turin, Dipartimento Fis Gen, I-10125 Turin, Italy. Monash Univ, Dept Math, Clayton, Vic 3168, Australia. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Amari, S (reprint author), Washington Univ, Space Sci Lab, 1 Brookings Dr, St Louis, MO 63130 USA. EM sa@howdy.wustl.du; nittler@lepvax.gsfc.nasa.gov; ekz@howdy.wustl.edu; gallino@ph02xd.ph.unito.it; marial@thala.maths.monash.edu.au; royl@rainbow.uchicago.edu NR 99 TC 83 Z9 83 U1 0 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2001 VL 546 IS 1 BP 248 EP 266 DI 10.1086/318230 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 390DL UT WOS:000166280400022 ER PT J AU Chan, KW Roellig, TL Onaka, T Mizutani, M Okumura, K Yamamura, I Tanabe, T Shibai, H Nakagawa, T Okuda, H AF Chan, KW Roellig, TL Onaka, T Mizutani, M Okumura, K Yamamura, I Tanabe, T Shibai, H Nakagawa, T Okuda, H TI Unidentified infrared emission bands in the diffuse interstellar medium SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; infrared : ISM : lines and bands ID POLYCYCLIC AROMATIC-HYDROCARBONS; CARBONACEOUS COMPOSITE QCC; PAH MOLECULES; ORION-BAR; UIR BANDS; DUST; FEATURES; SPECTRUM; IRTS; GAS AB Using the mid-infrared spectrometer on board the Infrared Telescope in Space and the low-resolution grating spectrometer (PHT-S) on board the Infrared Space Observatory, we obtained 820 mid-infrared (5-12 mum) spectra of the diffuse interstellar medium (DIM) in the Galactic center, W51, and Carina Nebula regions. These spectra indicate that the emission is dominated by the unidentified infrared (UIR) emission bands at 6.2, 7.7, 8.6, and 11.2 mum. The relative band intensities (6.2/7.7 mum, 8.6/7.7 mum, and 11.2/7.7 mum) were derived from these spectra, and no systematic variation in these ratios was found in our observed regions, in spite of the fact that the incident radiation intensity differs by a factor of 1500. Comparing our results with the polycyclic aromatic hydrocarbons (PAHs) model for the UIR band carriers, we find that PAHs in the DIM have no systematic variation in their size distribution, their degree of dehydrogenation is independent of the strength of UV radiation field, and they are mostly ionized. The finding that PAHs in the DIM with low UV radiation field strength are mostly ionized is incompatible with past theoretical studies, in which a large fraction of neutral PAHs is predicted in this kind of environment. A plausible resolution of this discrepancy is that the recombination coefficients for electron and large PAH positive ion are by at least an order of magnitude less than those adopted in past theoretical studies. Because of the very low population of neutral state molecules, photoelectric emission from interstellar PAHs is probably not the dominant source of heating of the diffuse interstellar gas. The present results imply constant physical and chemical properties of the carriers of the UIR emission bands in the DIM covering the central and disk regions of the Galaxy, which could help in the identification of the carriers. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Tokyo, Dept Astron, Bunkyo Ku, Tokyo 1130033, Japan. Commun Res Lab, Tokyo 1848795, Japan. Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. Univ Tokyo, Astron Inst, Tokyo 1818588, Japan. Nagoya Univ, Dept Phys, Chikusa Ku, Nagoya, Aichi 4648602, Japan. Gunma Astron Observ, Gunma 3770702, Japan. RP Chan, KW (reprint author), Univ Tokyo, Dept Astron, Bunkyo Ku, Tokyo 1130033, Japan. NR 51 TC 40 Z9 40 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2001 VL 546 IS 1 BP 273 EP 278 DI 10.1086/318260 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 390DL UT WOS:000166280400024 ER PT J AU Rodgers, SD Charnley, SB AF Rodgers, SD Charnley, SB TI Chemical differentiation in regions of massive star formation SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : abundances; ISM : clouds; ISM : molecules; molecular processes; stars : formation ID GHZ SPECTRAL SURVEY; HOT CORES; SAGITTARIUS B2; CHEMISTRY; AMMONIA; W3(OH); MOLECULES; CLOUDS; RESOLUTION; OMC-1 AB We have reexamined the origin of the apparent differentiation between nitrogen-bearing molecules and complex oxygen-bearing molecules that is observed in hot molecular cores associated with massive protostars. Observations show that methanol is an ubiquitous and abundant component of protostellar ices. Recent observations suggest that ammonia may constitute an appreciable fraction of the ices toward some sources. In contrast to previous theories that suggested that N/O differentiation was caused by an anticorrelation between methanol and ammonia in the precursor grain mantles, we show that the presence of ammonia in mantles and the core temperature are key quantities in determining N/O differentiation. Calculations are presented which show that when large amounts of ammonia are evaporated alkyl cation transfer reactions are suppressed and the abundances of complex O-bearing organic molecules greatly reduced. Cooler cores (100 K) eventually evolve to an oxygen-rich chemical state similar to that attained when no ammonia was injected, but on a timescale that is an order of magnitude longer (similar to 10(5) yr). Hotter cores (300 K) never evolve an O-rich chemistry unless ammonia is almost absent from the mantles. In this latter case, a complex O-rich chemistry develops on a timescale of similar to 10(4) yr, as in previous models, but disappears in about 2 X 10(5) yr, after which time the core is rich in NH3, HCN, and other N-bearing molecules. There are thus two ways in which N-rich cores can occur. We briefly discuss the implications for the determination of hot-core ages and for explaining N/O differentiation in several well-studied sources. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Rodgers, SD (reprint author), NASA, Ames Res Ctr, Div Space Sci, MS 245-3, Moffett Field, CA 94035 USA. RI Charnley, Steven/C-9538-2012 NR 40 TC 94 Z9 94 U1 2 U2 7 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2001 VL 546 IS 1 BP 324 EP 329 DI 10.1086/318263 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 390DL UT WOS:000166280400028 PM 11878346 ER PT J AU Nayakshin, S Kallman, TR AF Nayakshin, S Kallman, TR TI Accretion disk models and their X-ray reflection signatures. I. Local spectra SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; line : formation; radiation mechanisms : nonthermal; radiative transfer; X-rays : general ID ACTIVE GALACTIC NUCLEI; COLD MATTER; COMPTON REFLECTION; CYGNUS X-1; CORONAE; RADIATION; BINARIES; FLUORESCENCE; SYSTEMS; WINDS AB X-ray illumination of accretion disks is an invaluable diagnostic of the structure of these disks because of the associated iron K alpha emission. Here we point out that the resulting reflected spectra depend very sensitively on the geometry of the X-ray source and that this fact can be efficiently used to test these models observationally. In particular, we discuss three different accretion disk geometries : the "lamppost model," accretion disks with magnetic flares, and the model with a full corona overlaying a cold thin disk. We show that in the case of the lamppost model, unless the X-ray luminosity of the central source is larger than that of the cold disk by a factor of 10 or more, a significant fraction of iron in the ionized skin of the disk is in the hydrogen and helium-like ions. Because these ions have large fluorescence yields, the resulting reflected spectra look strongly ionized, with equivalent width (EW) of the line increasing with X-ray luminosity L-X up to the maximum of similar to 500 eV. This situation contrasts to the magnetic flare model, where the large X-ray flux near flares completely ionizes the skin of the disk and thus the resulting spectra appear to be that from a neutral material. The line EW in this model anti-correlates with X-ray luminosity and becomes arbitrarily small when L-X is a good fraction of the Eddington luminosity. Finally, in the full corona case, due to the additional pressure and weight of the corona, the gas pressure (and its density) below the corona is always large enough to make the gas very cool and effectively neutral. No highly ionized skin forms in such a model. If the corona is Thomson thin, then EW of the line does not depend on the accretion disk or corona luminosities for the full corona model. C1 NASA, Goddard Space Flight Ctr, High Energy Phys Lab, Greenbelt, MD 20771 USA. RP Nayakshin, S (reprint author), NASA, Goddard Space Flight Ctr, High Energy Phys Lab, Code 661, Greenbelt, MD 20771 USA. NR 59 TC 92 Z9 92 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2001 VL 546 IS 1 BP 406 EP 418 DI 10.1086/318250 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 390DL UT WOS:000166280400037 ER PT J AU Done, C Nayakshin, S AF Done, C Nayakshin, S TI Observational signatures of X-ray-irradiated accretion disks SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; line : formation; radiation mechanisms : nonthermal; radiative transfer; X-rays : general ID ACTIVE GALACTIC NUCLEI; ADVECTION-DOMINATED ACCRETION; COLD MATTER; CYGNUS X-1; BLACK-HOLE; SPECTRAL EVOLUTION; REFLECTION SPECTRA; IRON LINE; BINARIES; CORONA AB Reflection of X-rays from cool material around a black hole is one of the few observational diagnostics of the accretion flow geometry. Models of this reflected spectrum generally assume that the accretion disk can be characterized by material in a single ionization state. However, several authors have recently stressed the importance of the classic ionization instability for X-ray-irradiated gas in hydrostatic balance. This instability leads to a discontinuous transition in the vertical structure of the disk, resulting in a hot ionized skin above much cooler material. If the Compton temperature of the skin is high, then even iron is completely ionized, and the skin does not produce any spectral features. These new models, where the ionization structure of the disk is calculated self-consistently, require an excessive amount of computing power and so are difficult to use in directly fitting observed X-ray spectra. Instead, we invert the problem by simulating X-ray spectra produced by the new reflection models and then fit these with the old, single-zone reflection models, to assess the extent to which the derived accretion geometry depends on the reflection model used. We find that the single-zone ionization models can severely underestimate the covering fraction of the "cold" material as seen from the X-ray source if the optical depth in the ionized skin is of order unity and that this can produce an apparent correlation between the covering fraction and the X-ray spectral index similar in nature to that reported by Zdziarski, Lubinski, and Smith. C1 Univ Durham, Dept Phys, Durham DH1 3LE, England. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Done, C (reprint author), Univ Durham, Dept Phys, South Rd, Durham DH1 3LE, England. RI done, chris/D-4605-2016 OI done, chris/0000-0002-1065-7239 NR 64 TC 26 Z9 26 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2001 VL 546 IS 1 BP 419 EP 428 DI 10.1086/318245 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 390DL UT WOS:000166280400038 ER PT J AU Becker, PA Kazanas, D AF Becker, PA Kazanas, D TI Exact expressions for the critical Mach numbers in the two-fluid model of cosmic-ray-modified shocks SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; cosmic rays; methods : analytical; shock waves ID PARTICLE-MODIFIED SHOCKS; 2-FLUID MODELS; STEADY-STATE; ALFVEN WAVES; ACCELERATION; INJECTION; INSTABILITY; FRONTS; HYDRODYNAMICS; STABILITY AB The acceleration of relativistic particles due to repeated scattering across a shock wave remains the most attractive model for the production of energetic cosmic rays. This process has been analyzed extensively during the past two decades using the "two-fluid" model of diffusive shock acceleration. It is well known that one, two, or three distinct solutions for the flow structure can be found depending on the upstream parameters. Interestingly, in certain cases both smooth and discontinuous transitions exist for the same values of the upstream parameters. However, despite the fact that such multiple solutions to the shock structure were known to exist, the precise nature of the critical conditions delineating the number and character of shock transitions has remained unclear, mainly due to the inappropriate choice of parameters used in the determination of the upstream boundary conditions. In this paper we derive the exact critical conditions by reformulating the upstream boundary conditions in terms of two individual Mach numbers defined with respect to the cosmic-ray and gas sound speeds, respectively. The gas and cosmic-ray adiabatic indices are assumed to remain constant throughout the flow, although they may have arbitrary, independent values. Our results provide for the first time a complete, analytical classification of the parameter space of shock transitions in the two-fluid model. We use our formalism to analyze the possible shock structures for various values of the cosmic-ray and gas adiabatic indices. When multiple solutions are possible, we propose using the associated entropy distributions as a means for identifying the most stable configuration. C1 George Mason Univ, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. George Mason Univ, Dept Phys & Astron, Fairfax, VA 22030 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Becker, PA (reprint author), George Mason Univ, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. NR 38 TC 18 Z9 19 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2001 VL 546 IS 1 BP 429 EP 446 DI 10.1086/318257 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 390DL UT WOS:000166280400039 ER PT J AU Cuzzi, JN Hogan, RC Paque, JM Dobrovolskis, AR AF Cuzzi, JN Hogan, RC Paque, JM Dobrovolskis, AR TI Size-selective concentration of chondrules and other small particles in protoplanetary nebula turbulence SO ASTROPHYSICAL JOURNAL LA English DT Article DE planetary systems; solar system : formation; stars : formation ID FULLY-DEVELOPED TURBULENCE; HOMOGENEOUS ISOTROPIC TURBULENCE; SHOCK-WAVE MODEL; ACCRETION DISKS; SOLAR NEBULA; PREFERENTIAL CONCENTRATION; HYDRODYNAMICAL TURBULENCE; DUST COAGULATION; HEAVY-PARTICLES; TRANSPORT AB Size-selective concentration of particles in a weakly turbulent protoplanetary nebula may be responsible for the initial collection of chondrules and other constituents into primitive body precursors. This paper presents the main elements of this process of turbulent concentration. In the terrestrial planet region, both the characteristic size and size distribution of chondrules are explained. "Fluffier" particles would be concentrated in nebula regions that were at a lower gas density and/or more intensely turbulent. The spatial distribution of concentrated particle density obeys multifractal scaling, suggesting a close tie to the turbulent cascade process. This scaling behavior allows predictions of the probability distributions for concentration in the protoplanetary nebula to be made. Large concentration factors (>10(5)) are readily obtained, implying that numerous zones of particle density significantly exceeding the gas density could exist. If most of the available solids were actually in chondrule-sized particles, the ensuing particle mass density would become so large that the feedback effects on gas turbulence due to mass loading could no longer be neglected. This paper describes the process, presenting its basic elements and some implications, without including the effects of mass loading. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Symtech Inc, Arlington, VA USA. SETI Inst, Moffett Field, CA USA. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. RP Cuzzi, JN (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 88 TC 188 Z9 191 U1 0 U2 10 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2001 VL 546 IS 1 BP 496 EP 508 DI 10.1086/318233 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 390DL UT WOS:000166280400044 ER PT J AU Bell, RA Balachandran, SC Bautista, M AF Bell, RA Balachandran, SC Bautista, M TI The importance of FeI as a continuous opacity source in the solar atmosphere SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : abundances; Sun : atmosphere; Sun : photosphere; Sun : rotation; Sun : UV radiation ID ANGULAR-MOMENTUM TRANSPORT; STELLAR RADIATIVE ZONES; BERYLLIUM ABUNDANCES; EVOLUTION; HYDROGEN; MODELS; LIGHT; IRON; SUN; OH AB The inability of theoretical model fluxes to fit the observed solar flux in the UV, the "missing UV opacity problem," results in erroneous abundances derived from UV lines. For example, S. Balachandran and R. A. Bell recently argued that the solar beryllium abundance, derived from Be II lines at 3130 Angstrom, was not depleted but rather equal to the meteoritic value with critical implications on mixing and angular momentum transport models. In this Letter we have incorporated recent Iron Project calculations of the Fe I bound-free opacity into our calculations of the continuous opacity. By combining this with observed line blocking, we compare the predicted fluxes to the observed solar flux in the 2000-4000 Angstrom region. We find that a reasonable fit to the observed flux between 3000 and 4000 Angstrom is obtained with twice the Fe I bound-free value recently derived by M. A. Bautista. The importance of this and other metal bound-free opacities is discussed. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, High Energy Phys Lab, Greenbelt, MD 20771 USA. RP Bell, RA (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NR 30 TC 30 Z9 30 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2001 VL 546 IS 1 BP L65 EP L68 DI 10.1086/318059 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 393EV UT WOS:000166457000015 ER PT J AU Sambruna, RM Brandt, WN Chartas, G Netzer, H Kaspl, S Garmire, GP Nousek, JA Weaver, KA AF Sambruna, RM Brandt, WN Chartas, G Netzer, H Kaspl, S Garmire, GP Nousek, JA Weaver, KA TI X-ray imaging of the Seyfert 2 galaxy Circinus with Chandra SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (Circinus); galaxies : nuclei; galaxies : Seyfert; X-rays : galaxies ID EMISSION; NGC-1068 AB We present results from the zero-order imaging of a Chandra High-Energy Transmission Grating Spectrometer observation of the nearby Seyfert 2 galaxy Circinus. Twelve X-ray sources were detected in the Advanced CCD Imaging Spectrometer-S (ACIS-S) image of the galaxy, embedded in diffuse X-ray emission. The latter shows a prominent (similar to 18 ") soft "plume" in the northwest direction, coincident with the [O III] ionization cone. The radial profiles of the brightest X-ray source at various energies are consistent with an unresolved (FWHM similar to 0.8 ") component, which we identify as the active nucleus, plus two extended components with FWHM similar to 2.3 " and 18 ", respectively. In a radius of 3 ", the nucleus contributes roughly the same flux as the extended components at the softest energies (less than or similar to 2 keV). However, at harder energies (>2 keV), the contribution of the nucleus is dominant. The zero-order ACIS spectrum of the nucleus exhibits emission lines at both soft and hard X-rays, including a prominent Fe K alpha line at 6.4 keV, showing that most of the X-ray lines previously detected with ASCA originate in a compact region (less than or similar to 15 pc). Based on its X-ray spectrum, we argue that the 2.3 " extended component is scattered nuclear radiation from nearby ionized gas. The large-scale extended component includes the emission from the northwest plume and possibly from the outer starburst ring. C1 Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Sambruna, RM (reprint author), Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. RI Brandt, William/N-2844-2015 OI Brandt, William/0000-0002-0167-2453 NR 23 TC 28 Z9 28 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2001 VL 546 IS 1 BP L9 EP L12 DI 10.1086/318067 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 393EV UT WOS:000166457000003 ER PT J AU Sambruna, RM Netzer, H Kaspi, S Brandt, WN Chartas, G Garmire, GP Nousek, JA Weaver, KA AF Sambruna, RM Netzer, H Kaspi, S Brandt, WN Chartas, G Garmire, GP Nousek, JA Weaver, KA TI High-resolution X-ray spectroscopy of the Seyfert 2 galaxy Circinus with Chandra SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (Circinus); galaxies : nuclei; alaxies : Seyfert; X-rays : galaxies ID ASCA OBSERVATIONS AB Results from a 60 ks Chandra High-Energy Transmission Grating Spectrometer observation of the nearby Seyfert 2 galaxy Circinus are presented. The spectrum shows a wealth of emission lines at both soft and hard X-rays, including lines of Ne, Mg, Si, S, Ar, Ca, and Fe, and a prominent Fe K alpha line at 6.4 keV. We identify several of the He-like components and measure several of the Lyman lines of the H-like ions. The lines' profiles are unresolved at the limited signal-to-noise ratio of the data. Our analysis of the zero-order image in a companion Letter constrains the size of the emission region to be 20-60 pc, suggesting that emission within this volume is almost entirely due to the reprocessing of the obscured central source. Here we show that a model containing two distinct components can reproduce almost all the observed properties of this gas. The ionized component can explain the observed intensities of the ionized species, assuming twice-solar composition and an N proportional to r(-1.5) density distribution. The neutral component is highly concentrated, well within the 0.8 " point source, and is responsible for almost all of the observed K alpha (6.4 keV) emission. Circinus seems to be different than Mrk 3 in terms of its gas distribution. C1 Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Sambruna, RM (reprint author), Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. RI Brandt, William/N-2844-2015 OI Brandt, William/0000-0002-0167-2453 NR 13 TC 64 Z9 64 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2001 VL 546 IS 1 BP L13 EP L17 DI 10.1086/318068 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 393EV UT WOS:000166457000004 ER PT J AU Sandell, G Knee, LBG AF Sandell, G Knee, LBG TI NGC 1333 - Protostars, dust shells, and triggered star formation SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; dust, extinction; ISM : jets and outflows; ISM : molecules; stars : formation ID INITIAL MASS FUNCTION; MOLECULAR LINE; NGC-1333; CLOUD; EMISSION; OUTFLOWS; IRAS-2; NEBULA; CORE; JET AB We present large (13 ' x 18 ') and sensitive continuum maps at 850 and 450 mum of the NGC 1333 star formation region. We identify 33 submillimeter sources, some of which are extended and may contain multiple condensations. Very few of the submillimeter sources have optical or near-IR counterparts. In addition to the previously known bright class 0 sources, this survey suggests that many of the fainter sources are also likely to be very young low-mass protostars. We find several dust ridges and shells formed by outflows in the cloud, and in two cases we identify protostellar sources whose formation is likely to have been triggered by powerful outflow bow shocks. Thus, outflows have influenced the structure and evolution of the cloud over the entire area we have mapped. We derive a shallow dust clump mass spectrum, with dN/dM proportional to M-1.4 down to rather low masses, suggesting a large population of dust clumps in the brown dwarf mass range. C1 Natl Radio Astron Observ, Green Bank, WV 24944 USA. Natl Res Council Canada, Herzberg Inst Astrophys, Dominion Radio Astrophys Observ, Penticton, BC V2A 6K3, Canada. RP Sandell, G (reprint author), NASA, Ames Res Ctr, Univ Space Res Assoc, Moffett Field, CA 94035 USA. OI Knee, Lewis/0000-0002-9342-9003 NR 42 TC 82 Z9 82 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2001 VL 546 IS 1 BP L49 EP L52 DI 10.1086/318060 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 393EV UT WOS:000166457000011 ER PT J AU Yokoyama, T Akita, K Morimoto, T Inoue, K Newmark, J AF Yokoyama, T Akita, K Morimoto, T Inoue, K Newmark, J TI Clear evidence of reconnection inflow of a solar flare SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; plasmas; Sun : flares ID X-RAY TELESCOPE; MAGNETIC RECONNECTION; EJECTION; MISSION AB We found an important piece of evidence for magnetic reconnection inflow in a flare on 1999 March 18. The flare occurred on the northeast limb, displaying a nice cusp-shaped soft X-ray loop and a plasmoid ejection typical for the long-duration events. The EUV observation of the same flare shows us a bubble-like void ejection. The core of this EUV void corresponds to the soft X-ray plasmoid. Moreover, as this void is ejected, magnetic reconnection occurs at the disconnecting point. A clear ongoing pattern toward the magnetic X-point is seen. The velocity of this apparent motion is about 5 km s(-1), which is an upper limit on reconnection inflow speed. Based on this observation, we derive the reconnection rate as M-A = 0.001-0.03, where M-A is an Alfven Mach number of the inflow. C1 Nobeyama Radio Observ, Minamisa Ku, Nagano 3841305, Japan. Osaka Gakuin Univ, Osaka 5648511, Japan. Kyoto Univ, Kyoto 6068502, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Yokoyama, T (reprint author), Nobeyama Radio Observ, Minamisa Ku, Nagano 3841305, Japan. RI Yokoyama, Takaaki/B-9315-2008 OI Yokoyama, Takaaki/0000-0001-5457-4999 NR 15 TC 215 Z9 219 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2001 VL 546 IS 1 BP L69 EP L72 DI 10.1086/318053 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 393EV UT WOS:000166457000016 ER PT J AU Keenan, FP Crawford, FL Feibelman, WA Aller, LH AF Keenan, FP Crawford, FL Feibelman, WA Aller, LH TI Emission-line ratios for [N II] in gaseous nebulae and a comparison between theory and observation SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE atomic data; ISM : abundances; planetary nebulae : general ID SPACE-TELESCOPE OBSERVATIONS; FAINT OBJECT SPECTROGRAPH; COLLISION STRENGTHS; PLANETARY-NEBULAE; ATOMIC DATA; OPACITY CALCULATIONS; MAGELLANIC CLOUDS; ORION NEBULA; SPECTROSCOPY; SPECTRUM AB R-matrix calculations of electron impact excitation rates among the 2s(2)2p(2) P-3, D-1, S-1, and 2s2p(3) S-5 levels of N II are presented. These results are used in conjunction with other recent calculations of electron impact excitation rates and Einstein A-coefficients for N II to derive the emission-line ratio : ratio diagrams and where (R-1, R-2) (R-1, R-3), where R-1 = I(5756.2 Angstrom)/I(6549.9 + 6585.2 Angstrom), R-2 = I(2143.5 Angstrom)/I(6549.9 + 6585.2 Angstrom), and R-3 = I(2139.7 Angstrom)/I(6549.9 + 658.2 Angstrom), for a range of electron temperatures (T-e = 5000-20,000 K) and electron densities (N-e = 10(2)-10(7) cm(-3)) appropriate to gaseous nebulae. These diagrams should, in principle, allow the simultaneous determination of T-e and N-e from measurements of the [N II] lines in a spectrum. Plasma parameters deduced for a sample of gaseous nebulae, using observational data obtained from ground-based telescopes plus the International Ultraviolet Explorer and Hubble Space Telescope satellites, are found to show generally excellent internal consistency and to be in good agreement with the values of T-e and N-e estimated from other line ratios. These results provide observational support for the accuracy of the theoretical ratios and hence the atomic data adopted in their derivation. Theoretical ratios are also presented for the infrared line pair R-4 = I(122 mum)/I(205 mum), and the usefulness of R-4 as an electron density diagnostic is briefly discussed. C1 Queens Univ, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Calif Los Angeles, Dept Astron, Los Angeles, CA 90095 USA. RP Keenan, FP (reprint author), Queens Univ, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. NR 28 TC 7 Z9 7 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JAN PY 2001 VL 132 IS 1 BP 103 EP 106 DI 10.1086/318946 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 395QV UT WOS:000166593300006 ER PT J AU Snowden, SL Turner, TJ Freyberg, MJ AF Snowden, SL Turner, TJ Freyberg, MJ TI Temporal and spatial gain corrections for the ROSAT PSPC SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE instrumentation : detectors; space vehicles; X-rays : general ID ENERGY AB A calibration and a method for correction of the residual temporally dependent spatial-gain variation of the ROSAT PSPC are presented. When combined with the correction for the Prieto, Hasinger, & Snowden temporally dependent energy nonlinearity, these corrections provide a significant improvement in the consistency of fitted spectral parameters over the life of the PSPC. To derive the correction for the spatial gain variation, we use Al K alpha data (E similar to1.49 keV) from the on-board calibration sources to determine the gain as a function of detector position and time for 14, similar to 100 day intervals throughout the calibration/verification and Guest Observer phases of ROSAT operations. The resulting gain maps show residual variations of up to +/-4% in the gain around the mean channel used for the nominal PHA to PI channel conversion. The Prieto et al. results, an energy nonlinearity that peaks at similar to0.7 keV with a maximum reduction in the effective gain of similar to4.5%, and gain maps produced here are incorporated into correction algorithms that can be used on individual observations. We demonstrate the correction process using observations of the LMC supernova remnant N132D and the "Meaty" white dwarf performed at various times during the PSPC lifetime and at different positions across the detector for N132D. We find a significant improvement in the agreement of the fitted spectral parameter for the N132D spectrum, that has its peak emission at similar to0.8 keV. The Meaty results are marginal as the spectrum is particularly soft and not strongly affected by the Prieto et al. nonlinearity. The combined corrections aid in the comparison of source spectra from multiple observations spaced both in time and in position on the detector. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD USA. Univ Maryland, Baltimore, MD 21201 USA. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. RP Snowden, SL (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. RI Snowden, Steven/D-5292-2012 NR 11 TC 2 Z9 2 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JAN PY 2001 VL 132 IS 1 BP 107 EP 115 DI 10.1086/318942 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 395QV UT WOS:000166593300007 ER PT S AU White, NE AF White, NE BE Centrella, JM TI High energy astrophysics missions SO ASTROPHYSICAL SOURCES FOR GROUND-BASED GRAVITATIONAL WAVE DETECTORS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Workshop on Astrophysical Sources for Ground-Based Gravitational Wave Detectors CY OCT 30-NOV 01, 2000 CL DREXEL UNIV, PHILADELPHIA, PA HO DREXEL UNIV AB NASA's Structure and Evolution of the Universe (SEU) program uses X-ray and Gamma ray observations to observe the extremes of gravity throughout the universe. This program will probe the nature of black holes, ultimately obtaining a direct image of the event horizon. It will investigate the large scale structure of the Universe to constrain the location and nature of dark matter. Finally it will search for and study the highest energy processes, that approach those found in the early universe. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP White, NE (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0014-8 J9 AIP CONF PROC PY 2001 VL 575 BP 58 EP 65 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS56P UT WOS:000170337900006 ER PT S AU Swank, JH AF Swank, JH BE Centrella, JM TI X-ray observations of low-mass X-ray binaries: Accretion instabilities on long and short time-scales SO ASTROPHYSICAL SOURCES FOR GROUND-BASED GRAVITATIONAL WAVE DETECTORS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Workshop on Astrophysical Sources for Ground-Based Gravitational Wave Detectors CY OCT 30-NOV 01, 2000 CL DREXEL UNIV, PHILADELPHIA, PA HO DREXEL UNIV ID QUASI-PERIODIC OSCILLATIONS; SIDE-BAND; 4U-1820-30; DISCOVERY; NOVAE; MODEL AB X-rays trace accretion onto compact objects in binaries with low mass companions at rates ranging up to near Eddington. Accretion at high rates onto neutron stars goes through cycles with time-scales of days to months. At lower average rates the sources are recurrent transients; after months to years of quiescence, during a few weeks some part of a disk dumps onto the neutron star. Quasiperiodic oscillations near 1 kHz in the persistent X-ray flux attest to circular motion close to the surface of the neutron star. The neutron stars are probably inside their innermost stable circular orbits and the x-ray oscillations reflect the structure of that region. The long term variations show us the phenomena for a range of accretion rates. For black hole compact objects in the binary, the disk flow tends to be in the transient regime. Again, at high rates of flow from the disk to the black hole there are quasiperiodic oscillations in the frequency range expected for the innermost part of an accretion disk. There are differences between the neutron star and black hole systems, such as two oscillation frequencies versus one. For both types of compact object there are strong oscillations below 100 Hz. Interpretations differ on the role of the nature of the compact object. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Swank, JH (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 36 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0014-8 J9 AIP CONF PROC PY 2001 VL 575 BP 261 EP 272 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS56P UT WOS:000170337900023 ER PT S AU Strohmayer, TE AF Strohmayer, TE BE Centrella, JM TI X-ray observations of neutron star binaries: Evidence for millisecond spins SO ASTROPHYSICAL SOURCES FOR GROUND-BASED GRAVITATIONAL WAVE DETECTORS SE AIP Conference Proceedings LA English DT Proceedings Paper CT Workshop on Astrophysical Sources for Ground-Based Gravitational Wave Detectors CY OCT 30-NOV 01, 2000 CL DREXEL UNIV, PHILADELPHIA, PA HO DREXEL UNIV ID ROTATING RELATIVISTIC STARS; QUASI-PERIODIC OSCILLATIONS; GRAVITATIONAL-RADIATION; BRIGHTNESS OSCILLATIONS; COHERENT OSCILLATIONS; ANGULAR VELOCITIES; BURSTS; PULSAR; INSTABILITY; PROPAGATION AB High amplitude X-ray brightness oscillations during thermonuclear X-ray bursts were discovered with the Rossi X-ray Timing Explorer (RXTE) in early 1996. Spectral and timing evidence strongly supports the conclusion that these oscillations are caused by rotational modulation of the burst emission and that they reveal the spin frequency of neutron stars in low mass X-ray binaries (LMXB), a long sought goal of X-ray astronomy. I will briefly review the status of our knowledge of these oscillations. So far 10 neutron star systems have been observed to produce burst oscillations, interestingly, the observed frequencies cluster in a fairly narrow range from similar to 300 - 600 Hz, well below the break-up frequency for most modern neutron star equations of state (EOS). This has led to suggestions that their spin frequencies may be limited by the loss of angular momentum due to gravitational wave emission. Connections with gravity wave rotational instabilities will be briefly described. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Mail Code 662, Greenbelt, MD 20771 USA. NR 57 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0014-8 J9 AIP CONF PROC PY 2001 VL 575 BP 273 EP 283 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS56P UT WOS:000170337900024 ER PT J AU Heap, SR Hubeny, I Lanz, TM AF Heap, SR Hubeny, I Lanz, TM TI Properties of the Z=2.73 galaxy, MS1512-cB58 SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article DE galaxies : individual (MS1512-cB58); galaxies : evolution; cosmology : observations; ultraviolet AB MS1512-cB58 is an z=2.73 galaxy whose apparent brightness is amplified by30-50X due to gravitationally lensing. The restframe far-UV spectrum of cB58 that was obtained by Keck-I/LRIS is `one of the best ultraviolet spectra of a starburst galaxy obtained at any redshift' (Pettini et al., 2000). We have analyzed and modeled the spectrum of this galaxy in order to learn the properties of high-redshift galaxies. We find that our model spectrum is a near match to the observed spectrum of cB58 if the galaxy has a SMC-like metallicity, and has a Salpeter IMF extending up to similar to 100 M. The spectrum of cB58 also shows many absorption lines formed in a giant, expanding gas shell surrounding the star-forming complex. We show preliminary findings of the properties of the giant HII region based on our CLOUDSPEC model. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Heap, SR (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 277 SU 1 BP 263 EP 266 DI 10.1023/A:1012767508717 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 492KQ UT WOS:000172167900058 ER PT J AU Aellig, MR Lazarus, AJ Kasper, JC Ogilvie, KW AF Aellig, MR Lazarus, AJ Kasper, JC Ogilvie, KW TI Rapid measurements of solar wind ions with the Triana PlasMag Faraday Cup SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 2nd Meeting of the Observatory CY JAN 10-14, 2000 CL PARIS OBSERVATORY, MEUDON, FRANCE HO PARIS OBSERVATORY AB The Triana PlasMag Faraday Cup (FC) will be able to determine speed, flow angles, temperature, and density of the main solar wind ion species with a time resolution of better than one second. Thus, the Triana PlasMag FC will enable resolution of spatial structures as small as a few hundred kilometers as the structures convect past the spacecraft. Under typical solar wind conditions, that size is comparable to a few proton gyroradii. C1 MIT, Ctr Space Res, Cambridge, MA 02139 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Aellig, MR (reprint author), MIT, Ctr Space Res, Cambridge, MA 02139 USA. RI Kasper, Justin/D-1152-2010 OI Kasper, Justin/0000-0002-7077-930X NR 1 TC 4 Z9 4 U1 1 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 277 IS 1-2 BP 305 EP 307 DI 10.1023/A:1012229729242 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 486CC UT WOS:000171800000038 ER PT J AU Goldstein, ML AF Goldstein, ML TI Major unsolved problems in space plasma physics SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 2nd Meeting of the Observatory CY JAN 10-14, 2000 CL PARIS OBSERVATORY, MEUDON, FRANCE HO PARIS OBSERVATORY ID COLLISIONLESS MAGNETIC RECONNECTION; LARMOR RADIUS MAGNETOHYDRODYNAMICS; KELVIN-HELMHOLTZ INSTABILITY; SUPRATHERMAL TAIL STRENGTHS; SOLAR-WIND FLUCTUATIONS; ALFVEN WAVES; INCOMPRESSIBLE MAGNETOHYDRODYNAMICS; HALL MAGNETOHYDRODYNAMICS; INTERPLANETARY SHOCKS; EVOLVING FIELDS AB There are many space plasma physics problems that are both major and unsolved, there are other problems for which the categorization of solved or unsolved depends on one's point of view, and there are still other problems that are well understood but unsolved in the sense that quantitative predictions cannot be made although the basic physics is known. The following discussion will, of necessity, be limited and selective. The nature of the Alfvenic turbulence in the solar wind remains a major unsolved mystery: Why is the power spectrum of this anisotropic, compressible, magnetofluid often Kolmogoroff-like, with a power spectral index close to the -5/3 value characteristic of normal fluids? What is the three-dimensional symmetry of the turbulence? Are the magnetic fields quasi-two-dimensional and stochastic, or have they been highly refracted by small velocity shears? What is the origin of the -1 slope of the energy containing scales? What is the relationship between the turbulent fields and the diffusion coefficients for energetic particle transport parallel and perpendicular to the ambient magnetic field? A general problem in turbulence research is the relationship between the fluid approximation and the kinetic physics that describes the dissipation and damping of fluctuations. There is still much to learn about solar flares, coronal mass ejections and magnetospheric substorms. Another major puzzle is how to quantitatively describe the interaction of the solar wind with the interstellar medium; a problem probably not amenable to solution using fluid equations. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Goldstein, ML (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Goldstein, Melvyn/B-1724-2008 NR 80 TC 25 Z9 25 U1 1 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 277 IS 1-2 BP 349 EP 369 DI 10.1023/A:1012264131485 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 486CC UT WOS:000171800000048 ER PT J AU Colina, L Arribas, S Borne, KD AF Colina, L Arribas, S Borne, KD TI ULIRGs: Tidal-induced star formation and implications for SCUBA sources SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article ID INTEGRAL FIELD SPECTROSCOPY; INFRARED GALAXIES; REGIONS AB Integral field optical spectroscopy with the INTEGRAL fiber-fed system is used to investigate the properties of the tidal-induced star formation in the Ultraluminous Infrared Galaxy IRAS 12112+0305. Implications for the study of the SCUBA sources are briefly mentioned. C1 Fac Ciencias, UC, CSIC, Inst Fis Cantabria, Santander 39005, Spain. Inst Astrofis Canarias, Tenerife 38200, Spain. NASA, Raytheon Informat Technol & Sci Serv, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Colina, L (reprint author), Fac Ciencias, UC, CSIC, Inst Fis Cantabria, Avda Castros S-N, Santander 39005, Spain. NR 14 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 277 SU 1 BP 413 EP 416 DI 10.1023/A:1012784315019 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 492KQ UT WOS:000172167900099 ER PT J AU Ebisawa, K Kubota, A Mizuno, T Zycki, P AF Ebisawa, K Kubota, A Mizuno, T Zycki, P TI Accretion disk spectra of super-luminal jet sources and ultra-luminous compact X-ray sources in nearby spiral galaxies SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd Microquasar Workshop on Galactic Relativistic Jet Sources CY SEP 11-13, 2000 CL GRANADA, SPAIN SP Inst Astrofis Andaluc, Spainish Consejo Super Invest Cientif, Univ Barcelona, Lab Astrofis Espacial Fis Fdn, Inst Nacl Tecn Aerosp DE accretion disk; black hole; relativistic jet; X-ray sources ID GRO J1655-40; MASS; BINARIES AB The Ultra-luminous Compact X-ray Sources (ULXs) in nearby spiral galaxies and the Galactic super-luminal jet sources share the common spectral characteristic that they have extremely high disk temperatures which cannot be explained in the framework of the standard accretion disk model in the Schwarzschild metric. We have calculated an extreme Kerr disk model to examine if the Kerr disk model can instead explain the observed 'too hot' accretion disk spectra. We found that the Kerr disk spectrum becomes significantly harder compared to the Schwarzschild disk only when the disk is highly inclined. For super-luminal jet sources, which are known to be inclined systems, the Kerr disk model may thus work if we choose proper values for the black hole angular momentum. For the ULXs, however, the Kerr disk interpretation will be problematic, as is is highly unlikely that their accretion disks are preferentially inclined. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 113, Japan. Univ Space Res Assoc, Columbia, MD 21044 USA. Nicholas Copernicus Astron Ctr, PL-00716 Warsaw, Poland. RP Ebisawa, K (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 12 TC 4 Z9 4 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 276 SU S BP 11 EP 14 DI 10.1023/A:1011697718976 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 481BW UT WOS:000171500900005 ER PT J AU Feroci, M Casella, P Costa, E Massaro, E Soffitta, P Matt, G Belloni, T Castro-Tirado, AJ Dhawan, V Frontera, F Harmon, A Mirabel, F Pooley, G Tavani, M AF Feroci, M Casella, P Costa, E Massaro, E Soffitta, P Matt, G Belloni, T Castro-Tirado, AJ Dhawan, V Frontera, F Harmon, A Mirabel, F Pooley, G Tavani, M TI BeppoSAX observations of GRS 1915+105 SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd Microquasar Workshop on Galactic Relativistic Jet Sources CY SEP 11-13, 2000 CL GRANADA, SPAIN SP Inst Astrofis Andaluc, Spainish Consejo Super Invest Cientif, Univ Barcelona, Lab Astrofis Espacial Fis Fdn, Inst Nacl Tecn Aerosp DE X-ray sources; accretion disk; microquasar; GRS 1915+105 ID GRS-1915+105; BURSTS AB The galactic superluminal source GRS 1915+105 was observed by BeppoSAX at several occasions from October 1996 to April 2000. In April 1999 the 2-10 keV light curve showed a long series of quasi regular pulses with a recurrence time of about 50 s. Some preliminary results of a spectral analysis are presented. C1 CNR, Ist Astrofis Spaziale, Rome, Italy. Univ Roma Tre, Dipartimento Fis, Rome, Italy. Osserv Astron Brera, Merate, Italy. Ist Astrofis Andalucia, Granada, Spain. NRAO, Socorro, NM USA. CNR, Ist TESRE, I-40126 Bologna, Italy. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. CEA, Serv Astrophys, Saclay, France. Consejo Nacl Invest Cient & Tecn, IAFE, RA-1033 Buenos Aires, DF, Argentina. Mullard Radio Astron Observ, Cambridge, England. CNR, Ist Fis Cosmica, I-20133 Milan, Italy. RP Feroci, M (reprint author), CNR, Ist Astrofis Spaziale, Rome, Italy. OI Costa, Enrico/0000-0003-4925-8523; Feroci, Marco/0000-0002-7617-3421; Soffitta, Paolo/0000-0002-7781-4104; Castro-Tirado, A. J./0000-0003-2999-3563; Tavani, Marco/0000-0003-2893-1459; Casella, Piergiorgio/0000-0002-0752-3301 NR 11 TC 3 Z9 3 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 276 SU S BP 15 EP 18 DI 10.1023/A:1011601903046 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 481BW UT WOS:000171500900006 ER PT J AU Yamaoka, K Ueda, Y Inoue, H Nagase, F Ebisawa, K Kotani, T Tanaka, Y AF Yamaoka, K Ueda, Y Inoue, H Nagase, F Ebisawa, K Kotani, T Tanaka, Y TI Asca observations of the Galactic superluminal sources GRO J1655-40 and GRS 1915+105 SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd Microquasar Workshop on Galactic Relativistic Jet Sources CY SEP 11-13, 2000 CL GRANADA, SPAIN SP Inst Astrofis Andaluc, Spainish Consejo Super Invest Cientif, Univ Barcelona, Lab Astrofis Espacial Fis Fdn, Inst Nacl Tecn Aerosp DE GRO J1655-40; GRS 1915+105; X-ray : stars ID ABSORPTION-LINE FEATURES; RAY AB We summarize the ASCA observations of the two Galactic superluminal sources GRO J1655-40 and GRS 1915+105. focusing on the absorption line features. The high spectroscopic capability of ASCA enabled us to detect iron-K absorption line features from both objects. This is direct evidence for the presence of highly ionized plasma in a non-spherical configuration around a black hole, and is considered to be a unique signature of superluminal jet systems. The candidate of the line-absorber would be a part of an accretion disk at a distance of 10(9-11) cm from the central X-ray source. C1 Inst Space & Astronaut Sci, Kanagawa 2298501, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. RP Yamaoka, K (reprint author), Inst Space & Astronaut Sci, Yoshinodai 3-1-1, Kanagawa 2298501, Japan. NR 8 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 276 SU S BP 19 EP 22 DI 10.1023/A:1011653905772 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 481BW UT WOS:000171500900007 ER PT J AU Ueda, Y Yamaoka, K Grove, JE McCollough, M Durouchoux, P Rodriguez, J Mirabel, F Swank, J Feroci, M Casella, P Castro-Tirado, AJ Sanchez-Fernandez, C Chaty, S Castaneda, H Kohno, K Dhawan, V Trushkin, SA Ebisawa, K Kotani, T Inoue, H AF Ueda, Y Yamaoka, K Grove, JE McCollough, M Durouchoux, P Rodriguez, J Mirabel, F Swank, J Feroci, M Casella, P Castro-Tirado, AJ Sanchez-Fernandez, C Chaty, S Castaneda, H Kohno, K Dhawan, V Trushkin, SA Ebisawa, K Kotani, T Inoue, H CA Multiwavelength Campaign Team TI The 2000 April multiwavelength campaign of GRS 1915+105 SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd Microquasar Workshop on Galactic Relativistic Jet Sources CY SEP 11-13, 2000 CL GRANADA, SPAIN SP Inst Astrofis Andaluc, Spainish Consejo Super Invest Cientif, Univ Barcelona, Lab Astrofis Espacial Fis Fdn, Inst Nacl Tecn Aerosp DE GRS 1915+105; multiwavelength observations ID GRS-1915+105 AB We report results from multiwavelength observations of the microquasar GRS 1915+105 performed during the 2000 April campaign. This is one of the biggest campaigns ever made for this source covering the broad band from radio to gamma -rays. Multiwavelength light curves compiled from all the data reduced up to date and broad band spectra obtained with ASCA and RXTE are presented. C1 Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. USN, Res Lab, Washington, DC 20375 USA. NASA, MSFC, Huntsville, AL USA. Serv Astrophys, Saclay, France. Consejo Nacl Invest Cient & Tecn, IAFE, RA-1033 Buenos Aires, DF, Argentina. NASA, GSFC, Greenbelt, MD USA. CNR, Ist Astrofis Spaziale, I-00185 Rome, Italy. CSIC, IAA, Granada, Spain. INTA, LAEFF, Madrid, Spain. Open Univ, Dept Phys & Astron, Milton Keynes, Bucks, England. Observ Astron Nacl Mexico, Mexico City, DF, Mexico. NAO, Nobeyama Radio Observ, Nagano, Japan. NRAO, Charlottesville, VA USA. RP Ueda, Y (reprint author), Inst Space & Astronaut Sci, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229, Japan. RI Swank, Jean/F-2693-2012; OI Feroci, Marco/0000-0002-7617-3421; Castro-Tirado, A. J./0000-0003-2999-3563; Rodriguez, Jerome/0000-0002-4151-4468; Chaty, Sylvain/0000-0002-5769-8601; Casella, Piergiorgio/0000-0002-0752-3301 NR 6 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 276 SU S BP 25 EP 28 DI 10.1023/A:1011638928062 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 481BW UT WOS:000171500900009 ER PT J AU Hynes, RI Haswell, CA Chaty, S Shrader, CR Cui, W Mauche, CW AF Hynes, RI Haswell, CA Chaty, S Shrader, CR Cui, W Mauche, CW TI Recent Hubble space telescope results on X-ray novae SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd Microquasar Workshop on Galactic Relativistic Jet Sources CY SEP 11-13, 2000 CL GRANADA, SPAIN SP Inst Astrofis Andaluc, Spainish Consejo Super Invest Cientif, Univ Barcelona, Lab Astrofis Espacial Fis Fdn, Inst Nacl Tecn Aerosp ID MULTIWAVELENGTH AB RXTE has recently discovered two new optically bright black hole candidates (BHCs): XTE J1859+226 and XTE J1118+490. We observed both with HST/STIS, the first outburst observations of X-ray novae with this instrument. we followed broad band spectral evolution, detected correlated X-ray/UV rapid variability and performed high resolution UV spectroscopy. We present a summary of initial results on the spectral energy distributions observed. C1 Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. Open Univ, Dept Phys & Astron, Milton Keynes MK7 6AA, Bucks, England. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Hynes, RI (reprint author), Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. OI Cui, Wei/0000-0002-6324-5772; Chaty, Sylvain/0000-0002-5769-8601 NR 4 TC 0 Z9 0 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 276 SU S BP 61 EP 62 DI 10.1023/A:1011632122127 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 481BW UT WOS:000171500900018 ER PT J AU Maloney, P Colgan, S Cotera, A Hollenbach, D AF Maloney, P Colgan, S Cotera, A Hollenbach, D TI ISO observations of the Galactic Center black hole candidates 1E 1740.7-2942 and GRS 1758-258 SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd Microquasar Workshop on Galactic Relativistic Jet Sources CY SEP 11-13, 2000 CL GRANADA, SPAIN SP Inst Astrofis Andaluc, Spainish Consejo Super Invest Cientif, Univ Barcelona, Lab Astrofis Espacial Fis Fdn, Inst Nacl Tecn Aerosp ID MOLECULAR CLOUD; 1E-1740.7-2942 AB The Galactic Center black hole candidates IE 1740.7-2942 and GRS 1758 are luminous hard X-ray sources, with L-x > 10(37) erg s(-1). It has been suggested that both of these sources are powered by Bondi-Hoyle accretion from the ambient dense interstellar medium. If this is the case, luminous far-infrared fine-structure line emission should he detectable from both sources. We have obtained Infrared Space Observatory observations of both sources and failed to detect emission at the predicted levels, implying that either (1) the hard X-ray luminosities averaged over the last century are considerably lower (by factors of greater than or similar to 3 - 5) than presently, or (2) the mass of gas in immediate proximity to the sources is smaller than in the models (which assumed the X-ray sources were embedded in dense ISM) by about the same factor. Option (2) seems more likely, implying that these sources are not fueled by Bondi-Hoyle accretion. C1 Univ Colorado, CASA, Boulder, CO 80309 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Maloney, P (reprint author), Univ Colorado, CASA, Boulder, CO 80309 USA. NR 7 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 276 SU S BP 97 EP 98 DI 10.1023/A:1011613027579 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 481BW UT WOS:000171500900025 ER PT J AU Safi-Harb, S Durouchoux, P Petre, R AF Safi-Harb, S Durouchoux, P Petre, R TI The galactic microquasar W50/SS433 system SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd Microquasar Workshop on Galactic Relativistic Jet Sources CY SEP 11-13, 2000 CL GRANADA, SPAIN SP Inst Astrofis Andaluc, Spainish Consejo Super Invest Cientif, Univ Barcelona, Lab Astrofis Espacial Fis Fdn, Inst Nacl Tecn Aerosp ID SS-433 AB We review the X-ray and millimeter observations of the W50 lobes associated with the twin-jet source SS 433. This study is aimed at shedding light on the energetics from SS 433, understanding the asymmetries of the lobes, and testing for cosmic ray acceleration in a Galactic twin-jet source. C1 Univ Manitoba, Winnipeg, MB R3T 2N2, Canada. CEA, Saclay, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Safi-Harb, S (reprint author), Univ Manitoba, Winnipeg, MB R3T 2N2, Canada. NR 5 TC 1 Z9 1 U1 0 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 276 SU S BP 133 EP 134 DI 10.1023/A:1011610421644 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 481BW UT WOS:000171500900038 ER PT J AU Durouchoux, P Sood, R Safi-Harb, S Lu, FJ O'Neill, P Flohic, H Lefevre, F AF Durouchoux, P Sood, R Safi-Harb, S Lu, FJ O'Neill, P Flohic, H Lefevre, F TI Elongated SNRS: Possible new jet sources SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd Microquasar Workshop on Galactic Relativistic Jet Sources CY SEP 11-13, 2000 CL GRANADA, SPAIN SP Inst Astrofis Andaluc, Spainish Consejo Super Invest Cientif, Univ Barcelona, Lab Astrofis Espacial Fis Fdn, Inst Nacl Tecn Aerosp AB We summarise the properties of selected supernova remnants (SNRs) which have elongated envelopes that could house relativistic jets. We present MOPRA and SEST millimeter observations of these objects, showing correlation between known X-ray hot spots and molecular cloud density as signified by the detection of a CO(1-0) line flux. C1 CEA Saclay, DSM, DAPNIA, Serv Astrophys, F-91191 Gif Sur Yvette, France. Univ NSW, ADFA, Sch Phys, Canberra, ACT, Australia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. IHEP, Beijing, Peoples R China. RP Durouchoux, P (reprint author), CEA Saclay, DSM, DAPNIA, Serv Astrophys, F-91191 Gif Sur Yvette, France. NR 1 TC 1 Z9 1 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 276 SU S BP 139 EP 140 DI 10.1023/A:1011614523461 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 481BW UT WOS:000171500900040 ER PT J AU Swank, J AF Swank, J TI A review of disk-corona oscillations SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd Microquasar Workshop on Galactic Relativistic Jet Sources CY SEP 11-13, 2000 CL GRANADA, SPAIN SP Inst Astrofis Andaluc, Spainish Consejo Super Invest Cientif, Univ Barcelona, Lab Astrofis Espacial Fis Fdn, Inst Nacl Tecn Aerosp ID QUASI-PERIODIC OSCILLATIONS; MICROQUASAR GRO J1655-40; NOVA XTE J1550-564; X-RAY VARIABILITY; RXTE OBSERVATIONS; DISCOVERY; HZ; BINARIES AB Low frequency (approximate to 0.1-35 Hz) quasi-periodic oscillations of the X-ray flux characterize many of the black hole candidate.,,, in particular those which have radio evidence for jets. These QPO have amplitudes of up to 20% in the states of black hole novae which are called very high and intermediate and are correlated with the break frequency of the band-limited low frequency white noise. With transition to the state called the soft high state, both the QPO and the noise disappear. While the noise is strong in the low hard states like that of Cyg X-1, the QPO, when present, are weak and broad. In their strong manifestations, these QPO have the curious property of appearing to have thc spectrum of the power-law component which dominates in the low state, while correlations between their frequency and the disk component in the spectrum imply control by the disk. The correlations, the harmonic structure of the QPO, and the phase lags have complex behavior in the same source (GRS 1915+105, XTE J1550-564). The phenomena point to interaction between the disk and the corolla, for which there are several interesting ideas. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Swank, J (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Swank, Jean/F-2693-2012 NR 27 TC 8 Z9 8 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 276 SU S BP 201 EP 208 DI 10.1023/A:1011659800688 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 481BW UT WOS:000171500900053 ER PT J AU Markwardt, C AF Markwardt, C TI RXTE observations of the X-ray transient XTE J1859+226 SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd Microquasar Workshop on Galactic Relativistic Jet Sources CY SEP 11-13, 2000 CL GRANADA, SPAIN SP Inst Astrofis Andaluc, Spainish Consejo Super Invest Cientif, Univ Barcelona, Lab Astrofis Espacial Fis Fdn, Inst Nacl Tecn Aerosp AB We present results of RXTE observations of XTE J1859+226. a transient and probable microquasar discovered in October, 1999. The light curve approximately followed a fast-rise exponential-decay, with a peak flux of about 1.2 Crab (2-10 keV). The source is at a galactic latitude of +8.5 degrees. which makes it difficult to estimate distance and luminosity precisely. QPOs were detected in the 150-200 Hz and 0.5-10 Hz ranges, The high frequency QPOs and the results of spectral fitting can be used to loosely constrain the central object mass. C1 NASA, GSFC, Greenbelt, MD USA. Univ Maryland, College Pk, MD 20742 USA. RP Markwardt, C (reprint author), Univ Maryland, College Pk, MD 20742 USA. NR 13 TC 9 Z9 9 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 276 SU S BP 209 EP 212 DI 10.1023/A:1011616017526 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 481BW UT WOS:000171500900054 ER PT J AU Meier, DL AF Meier, DL TI Relativistic jet formation in microquasars SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd Microquasar Workshop on Galactic Relativistic Jet Sources CY SEP 11-13, 2000 CL GRANADA, SPAIN SP Inst Astrofis Andaluc, Spainish Consejo Super Invest Cientif, Univ Barcelona, Lab Astrofis Espacial Fis Fdn, Inst Nacl Tecn Aerosp ID DOUBLE RADIO-SOURCES; ACCRETION DISKS; BLACK-HOLES; MAGNETOHYDRODYNAMIC SIMULATIONS; ASTROPHYSICAL JETS; FLOWS; OUTFLOWS; ENERGY; MODEL AB Microquasars produce collimated, relativistic now at speeds up to a Lorentz factor of similar to 3 (0.94c). It is generally believed that Such now velocities indicate that jet acceleration and collimation occurs in the relativistic environment of a supermassive black hole. Recently, several groups around the world have begun to test theories of jet formation using magnetohydrodynamic (MHD) simulations of magnetized gas flow around black holes. This paper reviews the field of simulations of MHD jet formation, with an emphasis on producing the observed jet speeds and on the role that black hole angular momentum might play. It is shown that the most powerful jets occur when the black hole is rotating rapidly and when the accretion disk is geometrically thick and hot, This model may explain the association Of jet ejection with the hard state in microquasars. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Meier, DL (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 28 TC 1 Z9 1 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2001 VL 276 SU S BP 245 EP 252 DI 10.1023/A:1011685924737 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 481BW UT WOS:000171500900066 ER PT J AU Selzer, RH Mack, WJ Lee, PL Kwong-Fu, H Hodis, HN AF Selzer, RH Mack, WJ Lee, PL Kwong-Fu, H Hodis, HN TI Improved common carotid elasticity and intima-media thickness measurements from computer analysis of sequential ultrasound frames SO ATHEROSCLEROSIS LA English DT Article DE ultrasound; carotid artery; arterial stiffness; intima-media thickness; atherosclerosis; biomedical technology ID ARTERIAL STIFFNESS; WALL THICKNESS; B-MODE; ATHEROSCLEROSIS; RISK; HYPERCHOLESTEROLEMIA; HYPERTENSION; TRACKING; DISEASE; IMAGES AB B-mode ultrasound has gained popularity as a non-invasive method for direct visualization of superficial vessels. With B-mode ultrasound, arterial stiffness can be directly measured since image acquisition of the arterial wall thickness and vessel diameter can be obtained simultaneously in a dynamic fashion throughout the cardiac cycle. Recently, a method was developed to measure carotid arterial diameter and intima-media thickness (IMT) from B-mode images that utilizes computerized edge tracking-multiframe image processing that automatically measures arterial diameter and IMT in multiple sequential frames spanning several cardiac cycles. To evaluate this method, replicate B-mode common carotid artery ultrasound examinations and blood pressure measurements were obtained in 24 subjects 1-2 weeks apart. Approximately 80 sequential frames spanning two cardiac cycles were analyzed from each ultrasound examination to obtain maximum arterial diameter (D-max), minimum arterial diameter (D-min), and IMT using a computerized edge detection method. The intraclass correlations of D-max, D-min, and IMT were 0.97-0.99 and the mean absolute difference for these measurements were 0.03-0.11 mm. The coefficient of variation for D-max and D-min were 1.28 and 1.18%, respectively. The intraclass correlation for several standard arterial stiffness indices, Peterson's elastic modulus, Young's modulus, arterial distensibility, compliance, and the beta stiffness index ranged between 0.84 and 0.89. Additionally, it was determined that averaging IMT over five frames centered at D-min reduced single frame IMT measurement variability by 27% (P = 0.005) compared with IMT measured from a single frame corresponding to D-min. Comparison of the phasic relationship of D-max and D-min measured from the B-mode ultrasound image with the simultaneously recorded electrocardiogram (ECG) signal in the 24 subjects, provided a more accurate method of frame selection for arterial diameter extrema independent of the ECG signal. The method of computerized edge detection-sequential multiframe image processing presented in this paper represents a technological advance for image analysis of B-mode ultrasound images of common carotid arterial dimensions that is highly reproducible and directly applicable to noninvasive imaging of atherosclerosis. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved. C1 Univ So Calif, Sch Med, Dept Med, Div Cardiol,Atherosclerosis Res Unit, Los Angeles, CA 90033 USA. Univ So Calif, Sch Med, Dept Prevent Med, Los Angeles, CA 90033 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hodis, HN (reprint author), Univ So Calif, Sch Med, Dept Med, Div Cardiol,Atherosclerosis Res Unit, 2250 Alcazar St,CSC 132, Los Angeles, CA 90033 USA. FU NHLBI NIH HHS [R01HL-51913]; NIA NIH HHS [R01AG-13860, R01AG-15139] NR 26 TC 167 Z9 168 U1 0 U2 4 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0021-9150 J9 ATHEROSCLEROSIS JI Atherosclerosis PD JAN PY 2001 VL 154 IS 1 BP 185 EP 193 DI 10.1016/S0021-9150(00)00461-5 PG 9 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 387GZ UT WOS:000166116000023 PM 11137099 ER PT J AU Potter, C Genovese, VB Klooster, S Bobo, M Torregrosa, A AF Potter, C Genovese, VB Klooster, S Bobo, M Torregrosa, A TI Biomass burning losses of carbon estimated from ecosystem modeling and satellite data analysis for the Brazilian Amazon region SO ATMOSPHERIC ENVIRONMENT LA English DT Article ID NDVI DATA SET; CLIMATE VARIABILITY; NUTRIENT POOLS; AVHRR DATA; FIRE; NITROGEN; VEGETATION; ALLOCATION; FOREST; DYNAMICS AB To produce a new daily record of gross carbon emissions from biomass burning events and post-burning decomposition fluxes in the states of the Brazilian Legal Amazon (Instituto Brasileiro de Geografia e Estatistica (IBGE), 1991. Anuario Estatistico do Brasil, Vol. 51. Rio de Janeiro, Brazil pp. 1-1024). We have used vegetation greenness estimates from satellite images as inputs to a terrestrial ecosystem production model. This carbon allocation model generates new estimates of regional aboveground vegetation biomass at 8-km resolution. The modeled biomass product is then combined for the first time with fire pixel counts from the advanced very high-resolution radiometer (AVHRR) to overlay regional burning activities in the Amazon. Results from our analysis indicate that carbon emission estimates from annual region-wide sources of deforestation and biomass burning in the early 1990s are apparently three to five times higher than reported in previous studies for the Brazilian Legal Amazon (Houghton et al., 2000. Nature 403, 301-304; Fearnside, 1997. Climatic Change 35, 321-360), i.e., studies which implied that the Legal Amazon region tends toward a net-zero annual source of terrestrial carbon. In contrast, our analysis implies that the total source fluxes over the entire Legal Amazon region range from 0.2 to 1.2Pg Cyr(-1), depending strongly on annual rainfall patterns. The reasons for our higher burning emission estimates are (1) use of combustion fractions typically measured during Amazon forest burning events for computing carbon losses, (2) more detailed geographic distribution of vegetation biomass and daily fire activity for the region, and (3) inclusion of fire effects in extensive areas of the Legal Amazon covered by open woodland, secondary forests, savanna, and pasture vegetation. The total area of rainforest estimated annually to be deforested did not differ substantially among the previous analyses cited and our own. Published by Elsevier Science Ltd. C1 NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Moffett Field, CA 94035 USA. NASA, Ames Operat, Johnson Controls World Serv, Moffett Field, CA 94035 USA. Calif State Univ Monterey Bay, Seaside, CA 93955 USA. RP Potter, C (reprint author), NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Moffett Field, CA 94035 USA. OI Torregrosa, Alicia/0000-0001-7361-2241 NR 47 TC 25 Z9 28 U1 1 U2 13 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PY 2001 VL 35 IS 10 BP 1773 EP 1781 DI 10.1016/S1352-2310(00)00459-3 PG 9 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 415WB UT WOS:000167745600006 ER PT J AU Nguyen, LA Bualat, M Edwards, LJ Flueckiger, L Neveu, C Schwehr, K Wagner, MD Zbinden, E AF Nguyen, LA Bualat, M Edwards, LJ Flueckiger, L Neveu, C Schwehr, K Wagner, MD Zbinden, E TI Virtual reality interfaces for visualization and control of remote vehicles SO AUTONOMOUS ROBOTS LA English DT Article; Proceedings Paper CT IEEE International Conference on Robotics and Automation CY APR 24-28, 2000 CL SAN FRANCISCO, CALIFORNIA SP IEEE DE visualization; robotics; virtual reality; planetary exploration; user interfaces; remote control AB The Autonomy and Robotics Area (ARA) at NASA Ames Research Center has investigated the use of various types of Virtual Reality-based operator interfaces to remotely control complex robotic mechanisms. In this paper, we describe the major accomplishments and technology applications of the ARA in this area, and highlight the advantages and issues related to this technology. C1 NASA, Recom Technol Inc, Autonomy & Robot Area, Ames Res Ctr, Moffett Field, CA 94035 USA. NASA, Caelum Res Corp, Autonomy & Robot Area, Ames Res Ctr, Moffett Field, CA 94035 USA. NASA, Ames Associate, Autonomy & Robot Area, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Nguyen, LA (reprint author), NASA, Recom Technol Inc, Autonomy & Robot Area, Ames Res Ctr, Mail Stop 269-3, Moffett Field, CA 94035 USA. NR 11 TC 26 Z9 27 U1 2 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0929-5593 J9 AUTON ROBOT JI Auton. Robot. PY 2001 VL 11 IS 1 BP 59 EP 68 DI 10.1023/A:1011208212722 PG 10 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA 439YL UT WOS:000169145100007 ER PT J AU Muth, ER Raj, AK Rupert, AH AF Muth, ER Raj, AK Rupert, AH TI Untitled - Response SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Letter C1 Clemson Univ, Clemson, SC 29631 USA. Univ W Florida, Inst Human & Machine Cognit, Pensacola, FL 32514 USA. NASA, Lyndon B Johnson Space Ctr, Naval Aerosp Med Res Lab, Houston, TX USA. RP Muth, ER (reprint author), Clemson Univ, Clemson, SC 29631 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD JAN PY 2001 VL 72 IS 1 BP 74 EP 74 PG 1 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 389BM UT WOS:000166218800013 ER PT B AU Kolb, EW AF Kolb, EW BE Zichichi, A TI The dynamics of inflation SO BASICS AND HIGHLIGHTS IN FUNDAMENTAL PHYSICS SE SUBNUCLEAR SERIES LA English DT Proceedings Paper CT 37th Course of the International School of Subnuclear Physics CY AUG-SEP -, 1999 CL ERICE, ITALY SP Acad Sci Estonia, Acad Sci Georgia, Acad Sci Lithuania, Acad Sci Russia, Acad Sci Ukraine, Chinese Acad Sci, Italian Minist Univ & Sci Res, Italian Minist Educ, Sicilian Reg Govt, Weizmann Inst Sci, World Federat Scientists, World Lab ID SUPERDUSTER-VOID NETWORK; PARTICLE-PRODUCTION; POWER-SPECTRUM; UNIVERSE; MODELS AB In these lectures I will describe how we might be able to learn something of the dynamics during the inflationary era. C1 Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Dept Theoret Astrophys, Batavia, IL 60510 USA. RP Kolb, EW (reprint author), Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Dept Theoret Astrophys, MS 209 FNAL,Mail Stop 221,POB 500, Batavia, IL 60510 USA. NR 42 TC 0 Z9 0 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA PO BOX 128 FARRER RD, SINGAPORE 9128, SINGAPORE BN 981-02-4536-X J9 SUBNUCL SER PY 2001 VL 37 BP 210 EP 251 DI 10.1142/9789812811585_0008 PG 42 WC Physics, Multidisciplinary; Physics, Particles & Fields SC Physics GA BT22M UT WOS:000172333600007 ER PT S AU Scargle, JD AF Scargle, JD BE Rychert, JT Erickson, GJ Smith, CR TI Bayesian blocks SO BAYESIAN INFERENCE AND MAXIMUM ENTROPY METHODS IN SCIENCE AND ENGINEERING SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 19th International Workshop on Maximum Entropy and Bayesian Methods (MAXENT 99) CY AUG 02-05, 1999 CL BOISE STATE UNIV, BOISE, ID HO BOISE STATE UNIV ID CHANGE-POINT AB Identification of local structure in intensive data - such as time series, images, and higher dimensional processes - is an important problem in astronomy. Since the data are typically generated by an inhomogeneous Poisson process, an appropriate model is one that partitions the data space into cells, each of which is described by a homogeneous (constant event rate) Poisson process. It is key that the sizes and locations of the cells are determined by the data, and are not predefined or even constrained to be evenly spaced. For one-dimensional time series, the method amounts to Bayesian changepoint detection. Three approaches to solving the multiple changepoint problem are sketched, based on: (1) divide and conquer with single changepoints, (2) maximum posterior for the number of changepoints, and (3) cell coalescence. The last method starts from the Voronoi tessellation of the data, and thus should easily generalize to spaces of higher dimension. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Scargle, JD (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. NR 42 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0003-2 J9 AIP CONF PROC PY 2001 VL 567 BP 245 EP 256 PG 12 WC Computer Science, Artificial Intelligence; Physics, Mathematical; Statistics & Probability SC Computer Science; Physics; Mathematics GA BT70H UT WOS:000173805200014 ER PT J AU Koh, SD Conley, CA Sanders, KM AF Koh, SD Conley, CA Sanders, KM TI Stretch-dependent potassium channels in murine and canine colonic smooth muscle cells SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 Univ Nevada, Reno, NV 89557 USA. NASA, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD JAN PY 2001 VL 80 IS 1 MA 502 BP 111A EP 112A PN 2 PG 2 WC Biophysics SC Biophysics GA 397JH UT WOS:000166692200511 ER PT J AU Snell, EH Vahedi-Faridi, A Lovelace, J Bellamy, H Borgstahl, GEO AF Snell, EH Vahedi-Faridi, A Lovelace, J Bellamy, H Borgstahl, GEO TI A test of macromolecular crystallization in microgravity: Large, well-ordered insulin crystals SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 NASA, Struct Biol Lab, Huntsville, AL 35812 USA. Univ Toledo, Toledo, OH 43606 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD JAN PY 2001 VL 80 IS 1 MA 697 BP 180A EP 181A PN 2 PG 2 WC Biophysics SC Biophysics GA 397JH UT WOS:000166692200829 ER PT J AU Arakawa, ET Tuminello, PS Khare, BN Milham, ME AF Arakawa, ET Tuminello, PS Khare, BN Milham, ME TI Optical properties of ovalbumin in 0.130-2.50 mu m spectral region SO BIOPOLYMERS LA English DT Article DE optical properties; ovalbumin; complex index of refraction ID PROTEINS AB In our continuing series of measurements of the complex index of refraction for representative samples of biological materials, we measured ovalbumin (egg albumin) over the spectral region from 0.130 (76,923 cm(-1)) to 2.50 mum (4000 cm(-1)). Films of ovalbumin suitable for optical analyses were prepared and measured in addition to solutions of ovalbumin in water. We show several examples of how the methods used in this study produced accurate results for this complex and difficult to measure material. The present work is applicable to quantitative optical studies involving ovalbumin and other serpin proteins, as well as the study of proteinaceous toxins. (C) 2001 John Wiley & Sons, Inc. C1 Res & Technol Directorate, Edgewood Chem Biol Ctr, Aberdeen Proving Ground, MD 21010 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Milham, ME (reprint author), Res & Technol Directorate, Edgewood Chem Biol Ctr, Aberdeen Proving Ground, MD 21010 USA. NR 15 TC 11 Z9 11 U1 1 U2 5 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0006-3525 J9 BIOPOLYMERS JI Biopolymers PY 2001 VL 62 IS 2 BP 122 EP 128 DI 10.1002/bip.1004 PG 7 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 420AW UT WOS:000167982600005 PM 11288060 ER PT B AU Meier, DL Koide, S AF Meier, DL Koide, S BE Kaper, L VandenHeuvel, EPJ Woudt, PA TI The importance of rapid black hole spin in relativistic jet formation SO BLACK HOLES IN BINARIES AND GALACTIC NUCLEI: DIAGNOSTICS, DEMOGRAPHY AND FORMATION SE ESO ASTROPHYSICS SYMPOSIA LA English DT Proceedings Paper CT ESO International Workshop on Black Holes in Binaries and Galactic Nuclei - Diagnostics, Demography and Formation CY SEP 06-08, 1999 CL GARCHING, GERMANY SP ESO ID ACCRETION DISKS AB We present a summary of several recent papers on the simulation of relativistic jet formation in the vicinity of rotating and non-rotating black holes. We find that the strongest and fastest jets (Gamma similar to 3) occur when the hole is rotating and the disk plunges rapidly into the ergosphere. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91109 USA. RP Meier, DL (reprint author), CALTECH, Jet Propuls Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-41581-5 J9 ESO ASTROPHY SYMP PY 2001 BP 216 EP 217 DI 10.1007/10720995_44 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS56M UT WOS:000170337400044 ER PT B AU Lister, ML Smith, PS AF Lister, ML Smith, PS BE Padovani, P Urry, CM TI Intrinsic differences in the inner jets of high and low optically polarized radio quasars SO BLAZAR DEMOGRAPHICS AND PHYSICS, PROCEEDINGS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Blazar Demographics and Physics CY JUL 12-14, 2000 CL SPACE TELESCOPE SCI INST, BALTIMORE, MD HO SPACE TELESCOPE SCI INST ID COMPLETE SAMPLE AB We report on a high-resolution polarization study with the VLBA at 22 and 43 GHz of a sample of 18 high- and low-optically polarized, compact radio-loud quasars (HPQs and LPRQs, respectively). The polarization level of the unresolved parsec-scale radio core at 43 GHz and the overall optical polarization of the source are well correlated, suggesting a common (possibly co-spatial) origin. The electric vectors of the polarized 43 GHz radio cores are roughly aligned with the inner jet direction, indicating magnetic fields perpendicular to the flow. Similar orientations are seen in the optical, suggesting that the polarized flux at both wavelengths is due to one or more strong, transverse shocks located very close to the base of the jet. The LPRQs tend to have less luminous radio cores than the HPQs. and jet components with magnetic fields predominantly parallel to the jet. The components in HPQs jets, on the other hand, tend to have perpendicular magnetic field orientations. These differences cannot be entirely due to differences in jet orientation, and suggest that LPRQs may represent a quiescent phase of blazar activity, in which the inner jet flow does not undergo strong shocks. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lister, ML (reprint author), CALTECH, Jet Prop Lab, MS 238-332,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-059-5 J9 ASTR SOC P PY 2001 VL 227 BP 36 EP 39 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS52U UT WOS:000170231700006 ER PT S AU Yamaguchi, Y Fujisada, H Tsu, H Sato, I Watanabe, H Kato, M Kudoh, M Kahle, AB Pniel, M AF Yamaguchi, Y Fujisada, H Tsu, H Sato, I Watanabe, H Kato, M Kudoh, M Kahle, AB Pniel, M BE Tsuchiya, K TI ASTER early image evaluation SO CALIBRATION AND CHARACTERIZATION OF SATELLITE SENSORS AND ACCURACY OF DERIVED PHYSICAL PARAMETERS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT A0 2 Symposium of COSPAR Scientific Commission A held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Ctr Natl Etud Spatiale, European Org Exploitat Meteorol Satellites, European Space Agcy, Natl Aeronaut & Space Adm, Natl Ocean & Atmospher Adm, Natle Space Dev Agcy Japan, Comm Space Res ID INSTRUMENT; PERFORMANCE; DESIGN AB The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a high spatial resolution multi-spectral imaging radiometer,, and is onboard the NASA's Terra spacecraft launched on December 18, 1999. It spectrally covers the visible and near-infrared, short-wave-infrared, and thermal infrared regions with 14 spectral bands, and creates high-spatial-resolution (15-90 m) multispectral images of the Earth's surface. Referring to the baseline observation performance requirements provided by the ASTER Science Team, the ASTER early images were evaluated from both engineering and scientific points of view, e.g., general image quality, dynamic range, radiometric and geometric performance, etc. It was confirmed that the ASTER instrument generally exceeds the specified observation performance, and the early, images exhibit excellent quality even in the preliminary processing level. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Nagoya Univ, Chikusa Ku, Nagoya, Aichi 4648602, Japan. Sci Univ Tokyo, Noda, Chiba 2780022, Japan. Shikoku Natl Ind Res Inst, Takamatsu, Kagawa 7610395, Japan. Geol Survey Japan, Tsukuba, Ibaraki 3058567, Japan. Earth Remote Sensing Data Anal Ctr, Tokyo 1040054, Japan. Japan Resources Observ Syst Org, Tokyo 1040032, Japan. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yamaguchi, Y (reprint author), Nagoya Univ, Chikusa Ku, Nagoya, Aichi 4648602, Japan. NR 8 TC 14 Z9 15 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 28 IS 1 BP 69 EP 76 DI 10.1016/S0273-1177(01)00287-3 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT25A UT WOS:000172421700008 ER PT S AU Green, RO Pavri, B Boardman, J AF Green, RO Pavri, B Boardman, J BE Tsuchiya, K TI On-orbit calibration of an ocean color sensor with an underflight of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) SO CALIBRATION AND CHARACTERIZATION OF SATELLITE SENSORS AND ACCURACY OF DERIVED PHYSICAL PARAMETERS SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Review CT A0 2 Symposium of COSPAR Scientific Commission A held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Ctr Natl Etud Spatiale, European Org Exploitat Meteorol Satellites, European Space Agcy, NASA, NOAA, Natle Space Dev Agcy Japan, Comm Space Res ID AVIRIS AB Accurate calibration of ocean color sensors in the orbital environment is essential to achieve the objectives for which these sensors were proposed, developed, and launched. However, the trauma of launch and the orbital environment may cause changes in sensor calibration. An innovative approach to calibrating ocean color sensors uses the simultaneous underflight of the spaceborne ocean color sensor by a calibrated airborne imaging spectrometer. On May 20, 1997, the high-altitude Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) underflew the Ocean Color and Temperature Scanner (OCTS) onboard the Advanced Earth Observing System (ADEOS) satellite. AVIRIS measures the total upwelling spectral radiance from 400 to 2500 nm at 10-nm intervals at high radiometric and spatial resolution. This spectral range includes the eight ocean bands of OCTS. The spectral, radiometric, and spatial calibrations of AVIRIS are determined in the laboratory and validated in flight. The AVIRIS underflight was designed to match the observation geometry of OCTS. An ocean surface calibration target was determined based on common azimuth and zenith observation. The AVIRIS spectra of the calibration target were corrected to the top of the atmosphere radiance and convolved to the OCTS spectral, radiometric, and spatial characteristics. These AVIRIS data were then used in conjunction with the OCTS data to calculate an on-orbit calibration for OCTS with uncertainty analysis. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Calif Santa Barbara, Inst Computat Earth Syst Sci, Santa Barbara, CA 93106 USA. Analyt Imaging & Geophys LLC, Boulder, CO 80303 USA. RP Green, RO (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA USA. NR 14 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES-SERIES PY 2001 VL 28 IS 1 BP 133 EP 142 DI 10.1016/S0273-1177(01)00322-2 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT25A UT WOS:000172421700016 ER PT J AU Vander Wal, RL Ticich, TM Curtis, VE AF Vander Wal, RL Ticich, TM Curtis, VE TI Substrate-support interactions in metal-catalyzed carbon nanofiber growth SO CARBON LA English DT Article DE carbon nanotubes; catalyst support; catalytically grown carbon; baking; chemical vapor deposition ID FIELD-EMISSION; NANOTUBES; DISSOCIATION; REACTIVITY; ADSORPTION; PARTICLES; CLUSTERS; PLASMA AB Catalyst-support interactions are critical in CVD processes for nanotube synthesis. In this article, the relative contributions of the catalyst electronic structure and support chemical composition are evaluated with Cu, Fe and Ni as catalysts and Al2O3, CaO, SiO2 and TiO2 as support media. The impact of the interaction is judged qualitatively based on nanotube growth and structure. Results are interpreted in terms of electron charge donation to the metal nanoparticle enabled by either strong-metal support interaction (SMSI) or by interaction of the catalyst nanoparticle with exposed Lewis base sites on the support material. The role of the physical structure of the support medium is explored by comparison of nanotubes grown upon powdered and fumed phases of the support oxides. Carbon nanotubes catalyzed by metal nanoparticles generated in-situ or preformed illustrate the advantage of presynthesized particles for size uniformity with attendant greatly lessened dependence upon catalyst preparation conditions. Catalyst retention and dispersion under rapid heating conditions is evaluated for the same support-catalyst systems listed above as a preliminary test for flame synthesis. Results show that SMSI interaction is critical to using the supported catalyst method in a flame. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 NASA Glenn, NCMR, Cleveland, OH 44135 USA. Centenary Coll Louisiana, Dept Chem, Shreveport, LA 71134 USA. RP Vander Wal, RL (reprint author), NASA Glenn, NCMR, MS 110-3,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 33 TC 104 Z9 104 U1 7 U2 52 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0008-6223 J9 CARBON JI Carbon PY 2001 VL 39 IS 15 BP 2277 EP 2289 DI 10.1016/S0008-6223(01)00047-1 PG 13 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 495YJ UT WOS:000172367700003 ER PT S AU Andrews, R Mah, R Jeffrey, S Aghevli, A Freitas, K Guerrero, M Papasin, R Reed, C AF Andrews, R Mah, R Jeffrey, S Aghevli, A Freitas, K Guerrero, M Papasin, R Reed, C BE Lemke, HU Vannier, MW Inamura, K Farman, AG Doi, K TI Multisensor tissue identification: The NASA Smart Probe project SO CARS 2001: COMPUTER ASSISTED RADIOLOGY AND SURGERY SE INTERNATIONAL CONGRESS SERIES LA English DT Proceedings Paper CT 15th International Congress and Exhibition on Computer Assisted Radiology and Surgery CY JUN 27-30, 2001 CL BERLIN, GERMANY SP Amer Acad Oral & Maxillofacial Radiol, Bulgarian Assoc Radiol, British Inst Radiol, Czech Radiol Soc, Deutsch Gesell Biomed Tech eV, DRG, European Soc Engn & Med, Gesell Informatik, GMDS, Int Assoc Dento Maxillo Facial Radiol, IEEE, Informat Processing Med Imaging, Japanese Coll Radiol, Japan Radiol Soc, Japanese Soc Oral & Maxillofacial Radiol, Nederlandse Vereniging Radiol, ORG, Royal Coll Radiologists, Soc Francaise Radiol Med, Schweizer Gesell Med Radiol, Assoc Italiana Radiol Med, Chinese Soc Comp Assisted Radiol, SPIE, Slovak Radiol Soc, Techn Univ Berlin, World Acad Biomed Technologies DE brain tissue; breast cancer; computer; neural network; spectroscopy ID MULTIMODALITY C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Andrews, R (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0531-5131 BN 0-444-50866-X J9 INT CONGR SER PY 2001 VL 1230 BP 1145 EP 1145 PG 1 WC Computer Science, Interdisciplinary Applications; Radiology, Nuclear Medicine & Medical Imaging; Surgery SC Computer Science; Radiology, Nuclear Medicine & Medical Imaging; Surgery GA BT72A UT WOS:000173844800230 ER PT J AU Esteban, EP Vazquez, S AF Esteban, EP Vazquez, S TI Rotating stratified heterogeneous oblate spheroid in Newtonian physics SO CELESTIAL MECHANICS & DYNAMICAL ASTRONOMY LA English DT Article DE Euler equations; rotating spheroids; Earth's inner and outer cores AB By solving the Euler hydrodynamical equations we have obtained closed form solutions for the angular velocities and pressures of a three stratified non-confocal heterogeneous oblate spheroid. Limiting and particular solutions cases, such as a spheroid with N layers, a stratified spheroid with the same eccentricities, as well as confocal layered spheroids are also explicitly written down. As an application, we have numerically estimated planet Earth's outer and inner cores' ellipticities to be epsilon(o) = 1/413.318 and epsilon(i) = 1/424.616, respectively. These Earth's ellipticities values are in good agreement with those found in the literature. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Esteban, EP (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 15 TC 3 Z9 4 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0923-2958 J9 CELEST MECH DYN ASTR JI Celest. Mech. Dyn. Astron. PY 2001 VL 81 IS 4 BP 299 EP 312 DI 10.1023/A:1013292529030 PG 14 WC Astronomy & Astrophysics; Mathematics, Interdisciplinary Applications SC Astronomy & Astrophysics; Mathematics GA 518UL UT WOS:000173686200003 ER PT J AU Pohorille, A Wilson, MA AF Pohorille, A Wilson, MA TI Unassisted and assisted ion transport across membranes: Insights from computer simulations SO CELLULAR & MOLECULAR BIOLOGY LETTERS LA English DT Article; Proceedings Paper CT Conference on Biophysics and Biology of Environmentally Important Membrane-Active Compounds CY MAY 11-13, 2001 CL WROCLAW, POLAND ID BILAYERS; SELECTIVITY; MECHANISM; CHANNEL; MODEL C1 Univ Calif San Francisco, Dept Pharmaceut Chem, San Francisco, CA 94143 USA. NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. RP Pohorille, A (reprint author), Univ Calif San Francisco, Dept Pharmaceut Chem, San Francisco, CA 94143 USA. NR 13 TC 10 Z9 10 U1 0 U2 5 PU CELLULAR & MOLECULAR BIOLOGY LETTERS PI WROCLAW PA UNIV WROCLAW, INST BIOCHEM, DEPT GENETIC BIOCHEMISTRY, PRZBYSZEWSKIEGO 63/77, 51-148 WROCLAW, POLAND SN 1425-8153 J9 CELL MOL BIOL LETT JI Cell. Mol. Biol. Lett. PY 2001 VL 6 IS 2A BP 369 EP 374 PG 6 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 485AQ UT WOS:000171730500020 ER PT B AU Weaver, KA AF Weaver, KA BE Knapen, JH Beckman, JE Shlosman, I Mahoney, TJ TI X-ray properties of the central kpc of AGN and starbursts: The latest news from Chandra SO CENTRAL KILOPARSEC OF STARBURSTS AND AGN: THE LA PALMA CONNECTION SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on the Central Kiloparsec of Starbursts and AGN CY MAY 07-11, 2001 CL LOS CANCAJOS, SPAIN SP Isaac Newton Grp Telescopes ID GALACTIC NUCLEI; GALAXY NUCLEI; NGC 1068; EMISSION; CONSTRAINTS; EVOLUTION; NGC-3256; NGC-253 AB The X-ray properties of 15 nearby (upsilon < 3000 km s(-1)) galaxies that possess AGN and/or starbursts are discussed, Two-thirds have nuclear extended emission on scales from similar to 0.5 to similar to 1.5 kpc that is either clearly associated with a nuclear outflow or morphologically resembles an outflow. Galaxies that are AGN-dominated tend to have linear structures while starburst-dominated galaxies tend to have plume-like structures. Significant X-ray absorption is present in the starburst regions, indicating that a circumnuclear starburst is sufficient to block an AGN at optical wavelengths. Galaxies with starburst activity possess more X-ray point sources within their central kpc than non-starbursts. Many of these sources are more luminous than typical X-ray binaries. The Chandra results are discussed in terms of the starburst-AGN connection, a revised unified model for AGN, and possible evolutionary scenarios. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Weaver, KA (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 40 TC 17 Z9 17 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-089-7 J9 ASTR SOC P PY 2001 VL 249 BP 389 EP 410 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU54V UT WOS:000176290900052 ER PT B AU Mazzuca, LM Knapen, JH Regan, MW Boker, T AF Mazzuca, LM Knapen, JH Regan, MW Boker, T BE Knapen, JH Beckman, JE Shlosman, I Mahoney, TJ TI High-resolution imaging of stars, dust, and star formation in nuclear rings in galaxies SO CENTRAL KILOPARSEC OF STARBURSTS AND AGN: THE LA PALMA CONNECTION SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on the Central Kiloparsec of Starbursts and AGN CY MAY 07-11, 2001 CL LOS CANCAJOS, SPAIN SP Isaac Newton Grp Telescopes AB Nuclear rings in barred spiral galaxies offer an opportunity to study starburst properties, as well as the evolution of star formation in the central regions of galaxies. To further our understanding in these areas, a large imaging survey of over 80 galaxies with previous evidence for the existence of nuclear ring structure has been performed in the Ha emission line and the B and I broad bands using the William Herschel Telescope. Here, we present images of a subset of these galaxies, which reveal well-resolved nuclear rings in Ha. The rings consist of numerous "hotspots" (i.e., Ho-bright star-forming regions). For each hotspot we calculate Ha equivalent widths and compare the results to population synthesis models to obtain age estimates. Typical cluster ages are no more than 10 Myr. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mazzuca, LM (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt Rd, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-089-7 J9 ASTR SOC P PY 2001 VL 249 BP 573 EP 576 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU54V UT WOS:000176290900076 ER PT J AU Goldsby, JC AF Goldsby, JC TI High temperature mechanical behavior of polycrystalline alumina from mixed nanometer and micrometer powders SO CERAMICS INTERNATIONAL LA English DT Article DE hot pressing; mixing; mechanical properties; Al2O3 ID CERAMICS AB Sintered aluminum oxide materials were formed using commercial methods from mechanically mixed powders of nano- and micrometer alumina. The powders were consolidated at 1500 and 1600 degreesC with 3.2 and 7.2 ksi applied stress in argon. The conventional micrometer sized powders failed to consolidate. While 100% nanometer-sized alumina and its mixture with the micrometer powders achieved > 99% density. Preliminary high temperature creep behavior indicates no super-plastic strains. However high strains ( > 0.651%)were generated in the nanometer powder, due to cracks and linked voids initiated by cavitation. (C) 2001 Elsevier Science Ltd and Techna S.r.l. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Goldsby, JC (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 9 TC 10 Z9 12 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0272-8842 J9 CERAM INT JI Ceram. Int. PY 2001 VL 27 IS 6 BP 701 EP 703 DI 10.1016/S0272-8842(01)00023-2 PG 3 WC Materials Science, Ceramics SC Materials Science GA 463YK UT WOS:000170504700015 ER PT B AU Mazuruk, K AF Mazuruk, K BE Davis, GDV Leonardi, E TI Convective flow induced by localized traveling magnetic fields SO CHT'01: ADVANCES IN COMPUTATIONAL HEAT TRANSFER II, VOLS 1 AND 2, PROCEEDINGS LA English DT Proceedings Paper CT 2nd International Symposium on Advances in Computational Heat Transfer CY MAY 20-25, 2001 CL PALM COVE, AUSTRALIA SP Int Ctr Heat & Mass Transfer, Univ New S Wales, Computat Fluid Dynam Res Lab ID FLUID-FLOW; CRYSTALS; GROWTH AB An axisymmetric traveling magnetic field induces a meridional base flow in a cylindrical zone of an electrically conducting liquid. This remotely induced flow can be conveniently controlled, in magnitude and direction, and can have benefits for crystal growth applications. In particular, it can be used to offset natural convection. For long vertical cylinders, non-uniform and localized in the propagating direction, magnetic fields are required for this purpose. Here we investigate a particular form of this field, namely that induced by a set of a few electric current coils. An order of magnitude reduction of buoyancy convection is theoretically demonstrated for a vertical Bridgman crystal growth configuration. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35803 USA. RP Mazuruk, K (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35803 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU BEGELL HOUSE, INC PI NEW YORK PA 145 MADISON AVE, NEW YORK, NY 10016 USA BN 1-56700-158-0 PY 2001 BP 785 EP 790 PG 6 WC Thermodynamics; Engineering, Manufacturing; Engineering, Mechanical SC Thermodynamics; Engineering GA BT14C UT WOS:000172068000087 ER PT S AU Zimmerman, RJ Nance, JM AF Zimmerman, RJ Nance, JM BE Rabalais, NN TI Effects of hypoxia on the shrimp fishery of Louisiana and Texas SO COASTAL AND ESTUARINE SCIENCES, VOL 58: COASTAL HYPOXIA: CONSEQUENCES FOR LIVING RESOURCES AND ECOSYSTEMS SE COASTAL AND ESTUARINE SCIENCES LA English DT Proceedings Paper CT Workshop on Coastal and Estuarine Studies CY MAR, 1998 CL BATON ROUGE, LA ID PENAEUS-SETIFERUS LINNAEUS; AZTECUS IVES AB Large-scale hypoxia, recently approaching 20,000 km(2), overlaps with habitat and fishing grounds of commercial shrimp species in Louisiana and Texas shelf waters. It is expected that an environmental impact of this magnitude would have an effect on the shrimp population that is reflected in catch statistics. In this paper, we examine the geographic distribution and amount of shrimp catch in relation to location and size of the hypoxic zone. The results are interpreted in context with what is known about the life cycles and habits of the two shrimp species involved and the behavior of shrimp fisheries. A significant negative relationship was evident between catch of brown shrimp from Texas and Louisiana waters versus the relative size of the mid-summer hypoxic zone. In addition, Texas catch was significantly dependent upon Louisiana catch, a relationship that has become stronger since 1980. Catch per unit effort of brown shrimp also has declined significantly during a recent interval in which hypoxia was known to expand. Importantly, the same relationships were not significant between hypoxia and catches of white shrimp. As hypothesized, owing to their more offshore habitat requirements, brown shrimp were impacted to a greater degree than white shrimp. The annual success of shrimp fisheries, like most commercial fisheries, is highly related to environmental factors. The combined evidence indicates that hypoxia in Louisiana, due to its large area of coverage, has increased as an environmental factor for shrimp in recent decades. C1 Natl Marine Fisheries Serv, Galveston Lab, Galveston, TX 77551 USA. RP Zimmerman, RJ (reprint author), Natl Marine Fisheries Serv, Galveston Lab, 4700 Ave U, Galveston, TX 77551 USA. NR 33 TC 13 Z9 14 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0733-9569 BN 0-87590-272-3 J9 COAST EST S JI Coast. Est. S. PY 2001 VL 58 BP 293 EP 310 PG 18 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA BT70K UT WOS:000173805400015 ER PT S AU Fischer, DG Ovryn, B AF Fischer, DG Ovryn, B BE Tuchin, VV Izatt, JA Fujimoto, JG TI Phase shifting optical coherence tomography SO COHERENCE DOMAIN OPTICAL METHODS IN BIOMEDICAL SCIENCE AND CLINICA APPLICATIONS V SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on Coherence Domain Optical Methods in Biomedical Science and Clinical Applications V CY JAN 23-24, 2001 CL SAN JOSE, CA SP SPIE ID INTERFEROMETRY AB We demonstrate the use of phase-shifting interferometry in OCT to determine the optical phase and fringe visibility within the coherence envelope. Phase-shifting algorithms provide both the optical phase and visibility from a series of intensity measurements corresponding to controlled phase shifts. In addition to providing phase information which supplements the visibility or envelope data which is traditionally obtained in OCT, this technique will provide an independent, highly sensitive measurement of the coherence envelope which may be used for a precise determination of the source power spectrum. C1 NASA, Glenn Res Ctr, Natl Ctr Micrograv Res Fluids & Combust, Cleveland, OH 44135 USA. RP NASA, Glenn Res Ctr, Natl Ctr Micrograv Res Fluids & Combust, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM bxo3@po.cwru.edu NR 7 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3929-0 J9 PROC SPIE PY 2001 VL 4251 BP 97 EP 101 DI 10.1117/12.427878 PG 5 WC Engineering, Biomedical; Radiology, Nuclear Medicine & Medical Imaging SC Engineering; Radiology, Nuclear Medicine & Medical Imaging GA BS45U UT WOS:000169895900016 ER PT J AU Shaw, BD Aharon, I Lenhart, D Dietrich, DL Williams, FA AF Shaw, BD Aharon, I Lenhart, D Dietrich, DL Williams, FA TI Spacelab and drop-tower experiments on combustion of methanol/dodecanol and ethanol/dodecanol mixture droplets in reduced gravity SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article DE liquid droplets; microgravity flame phenomena ID METHANOL; EXTINCTION; ETHANOL; WATER AB This paper describes reduced-gravity experiments on the combustion of droplets composed of methanol/dodecanol and ethanol/dodecanol mixtures. The experiments used the NASA Glenn Research Center 2.2 s drop tower as well as facilities in Spacelab during the USML-2 flight. In the drop-tower experiments, initial droplet diameters ranged from 0,8 mm to 1.2 mm, initial dodecanol mass fractions, Y, (in both mixtures) were 0.1, 0.25 and 0,5, and the ambient gas mixture was either an O-2/He mixture (with a molar O-2 concentration of 0.5) or atmospheric air. Most drop-tower experiments were at 0.1 MPa ambient pressure, although two tests were at 0.04 MPa. In the Spacelab experiments. the methanol/dodecanol droplets burned in ambient shuttle air (0.21 oxygen mote fraction) at 0.1 MPa, the initial droplet sizes were in the range 4.2 train to 5.4 mm, and the initial values of Y were 0.2 and 0.4. Burning rates varied with experimental conditions, and disruptive burning was very frequent. One of the largest methanol/dodecanol droplets extinguished in an oscillatory fashion. Data on flame contractions, in combination with existing theoretical analyses. were used to infer effective liquid species diffusivities, D, that apply to these experiments. The D values varied slowly with composition for 0.25 less than or equal to Y less than or equal to 0.5. In this range. the theoretical values for liquid species diffusivities compare well with experimental values. The D values for Y < 0.25 varied rapidly with composition. and D values for Y = 0.1 were substantially smaller than for Y greater than or equal to 0.25. These variations in D are attributed to changes in liquid-liquid phase-equilibrium behaviors as liquid compositions change during combustion. Sooting was visually observed above threshold values of the initial dodecanol mass fraction (this threshold depended on the ambient conditions, and was different for methanol and ethanol). but only after flame contractions. C1 Univ Calif Davis, Davis, CA 95616 USA. NASA, Glenn Res Ctr, Cleveland, OH 44312 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. RP Shaw, BD (reprint author), Univ Calif Davis, Davis, CA 95616 USA. NR 37 TC 6 Z9 7 U1 2 U2 4 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK,, ABINGDON OX14 4RN, OXON, ENGLAND SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 2001 VL 167 BP 29 EP 56 DI 10.1080/00102200108952176 PG 28 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA 509KJ UT WOS:000173146700002 ER PT J AU Bahadori, MY Stocker, DP Zhou, L Hegde, U AF Bahadori, MY Stocker, DP Zhou, L Hegde, U TI Radiative loss from non-premixed flames in reduced-gravity environments SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article DE microgravity; partial gravity; radiation; g-jitter; diffusion flame; laminar flame; Moon; Mars ID JET DIFFUSION FLAMES; SHAPES AB This paper presents the results of an experimental and theoretical study of radiation from luminous jet diffusion flames in partial-gravity environments. Tests were conducted for laminar, non-premixed methane flames burning in quiescent air on-board the NASA KC-135 research aircraft for a range of gravity levels. Flame radiation and gravitational acceleration were measured, and flame imaging was performed. The radiation data are compared with those obtained from normal-gravity and microgravity tests, conducted in a drop facility. Effects of g-jitter on radiation measurements are discussed. With the aid of predictions from a numerical model of jet diffusion flames, the influence of gravity on radiation through its effects on the temperature, species, and velocity fields is analyzed. Good agreement between predictions and measurements is obtained. C1 Sci & Technol Dev Corp, Los Angeles, CA USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Sci Applicat Int Corp, Torrance, CA USA. Natl Ctr Micrograv Res, Cleveland, OH USA. RP Bahadori, MY (reprint author), Sci & Technol Dev Corp, Los Angeles, CA USA. NR 13 TC 1 Z9 1 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK,, ABINGDON OX14 4RN, OXON, ENGLAND SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 2001 VL 167 BP 169 EP 186 DI 10.1080/00102200108952181 PG 18 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA 509KJ UT WOS:000173146700007 ER PT J AU Takahashi, F Schmoll, WJ Strader, EA Belovich, VM AF Takahashi, F Schmoll, WJ Strader, EA Belovich, VM TI Suppression behavior of obstruction-stabilized pool flames SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article ID COUNTERFLOW DIFFUSION FLAMES; FIRE SUPPRESSANTS; EXTINCTION AB The suppression phenomena of a nonpremixed flame stabilized by a recirculation zone behind an obstruction in a combustion tunnel have been studied because of their relation to fires in aircraft engine nacelles, dry bays, and shipboard and ground-vehicle compartments. The JP-8 fuel was supplied as a liquid fuel pool, or a gaseous (methane or ethane) fuel issued from a flat porous plate. downstream of a backward-facing step or J-shape flange. The OH planar laser-induced fluorescence revealed a narrow. wrinkled diffusion flame zone that was deeply folded into the recirculation zone in response to the dynamic air entrainment and back-flow. Both transient and steady-state fire suppression limits were determined by impulsively injecting a gaseous fire-extinguishing agent (nitrogen, CF3Br, or C2HF5), or by continuously adding nitrogen, into the approaching airflow in the combustion tunnel. For high air velocities, the normalized critical agent mote fraction at suppression was a unique function of the agent injection period normalized by the effective mixing time in the recirculation zone, independent of types of fuels, agents, and obstacles. The extinction of the relatively low-strain-rate diffusion flame zone in the recirculation zone appears to determine the suppression limits of obstruction-stabilized flames. C1 Univ Dayton, Res Inst, Dayton, OH 45469 USA. USAF, Res Lab, Wright Patterson AFB, OH 45433 USA. RP Takahashi, F (reprint author), NASA, Natl Ctr Micrograv Res Fluids & Combust, Glenn Res Ctr, MS 500-115,21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 34 TC 4 Z9 5 U1 0 U2 7 PU GORDON BREACH PUBLISHING, TAYLOR & FRANCIS GROUP PI PHILADELPHIA PA 325 CHESTNUT ST, 8TH FL, PHILADELPHIA, PA 19106 USA SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 2001 VL 163 BP 107 EP + DI 10.1080/00102200108952153 PG 27 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA 473TW UT WOS:000171065000005 ER PT S AU Korsmeyer, DJ Schreiner, JA AF Korsmeyer, DJ Schreiner, JA BE Willett, PK Kirubarajan, T TI Assessment of the NASA Space Shuttle Program's problem reporting and corrective action system SO COMPONENT AND SYSTEMS DIAGNOSTICS, PROGNOSIS AND HEALTH MANAGEMENT SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Component and Systems Diagnostics, Prognosis, and Health Management CY APR 16-17, 2001 CL ORLANDO, FL SP SPIE DE PRACA; NASA Space Shuttle; problem reporting; databases AB This paper documents the general findings and recommendations of the Design for Safety Programs Study of the Space Shuttle Programs (SSP) Problem Reporting and Corrective Action (PRACA) System. The goals of this Study were; to evaluate and quantify the technical aspects of the SSP s PRACA systems, and to recommend enhancements addressing specific deficiencies in preparation for future system upgrades. The Study determined that the extant SSP PRACA systems accomplished a project level support capability through the use of a large pool of domain experts and a variety of distributed formal and informal database systems. This operational model is vulnerable to staff turnover and loss of the vast corporate knowledge that is not currently being captured by the PRACA system. A need for a Program-level PRACA system providing improved insight, unification, knowledge capture, and collaborative tools was defined is this study. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Korsmeyer, DJ (reprint author), NASA, Ames Res Ctr, MS 269-1, Moffett Field, CA 94035 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4084-1 J9 P SOC PHOTO-OPT INS PY 2001 VL 4389 BP 174 EP 185 DI 10.1117/12.434236 PG 12 WC Computer Science, Artificial Intelligence; Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BT21T UT WOS:000172292600018 ER PT S AU Krueger, R Minguet, PJ O'Brien, TK AF Krueger, R Minguet, PJ O'Brien, TK BE Grant, P Rousseau, CQ TI A method for calculating strain energy release rates in preliminary design of composite skin/stringer debonding under multiaxial loading SO COMPOSITE STRUCTURES: THEORY AND PRACTICE SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT Symposium on Composite Structures - Theory and Practice CY MAY 17-18, 1999 CL SEATTLE, WA SP ASTM Comm D 30 DE composite materials; delamination; fracture mechanics; energy release rate; finite-element analysis; virtual crack closure technique; skin/flange interface ID CRACK AB Three simple procedures were developed to determine strain energy release rates, G, in composite skin/stringer specimens for various combinations of uniaxial and biaxial (in-plane/out-of-plane) loading conditions. These procedures may be used for parametric design studies in such a way that only a few finite-element computations will be necessary for a study of many load combinations. The results were compared with mixed-mode strain energy release rates calculated directly from non-linear two-dimensional plane-strain finite-element analyses using the virtual crack closure technique. The first procedure involved solving three unknown parameters needed to determine the energy release rates. Good agreement was obtained when the external loads were used in the expression derived. This superposition technique, however, is applicable only if the structure exhibits a linear load/deflection behavior. Consequently, a second modified technique was derived which was applicable in the case of nonlinear load/deformation behavior. The technique, however, involved calculating six unknown parameters from a set of six simultaneous linear equations with data from six nonlinear analyses to determine the energy release rates. This procedure was not time efficient, and hence, less appealing. Finally, a third procedure was developed to calculate mixed-mode energy release rates as a function of delamination lengths. This procedure required only one nonlinear finite-element analysis of the specimen with a single delamination length to obtain a reference solution for the energy release rates and the scale factors. The delamination was subsequently extended in three separate linear models of the local area in the vicinity of the delamination subjected to unit loads to obtain the distribution of G with delamination lengths. This set of subproblems was solved using linear finite-element analyses, which resulted in a considerable reduction in CPU time compared to a series of nonlinear analyses. Although additional modeling effort is required to create the local submodel, this superposition technique is very efficient for large parametric studies, which may occur during preliminary design where multiple load combinations must be considered. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Krueger, R (reprint author), NASA, Langley Res Ctr, Mail Stop 188E, Hampton, VA 23681 USA. RI Krueger, Ronald/G-5356-2015 NR 18 TC 0 Z9 0 U1 1 U2 3 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2862-2 J9 AM SOC TEST MATER PY 2001 VL 1383 BP 105 EP 128 DI 10.1520/STP14506S PG 24 WC Materials Science, Composites SC Materials Science GA BS14C UT WOS:000168820900006 ER PT S AU Murri, GB AF Murri, GB BE Grant, P Rousseau, CQ TI Influence of ply waviness on fatigue life of tapered composite flexbeam laminates SO COMPOSITE STRUCTURES: THEORY AND PRACTICE SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT Symposium on Composite Structures - Theory and Practice CY MAY 17-18, 1999 CL SEATTLE, WA SP ASTM Comm D 30 DE marcel; ply waviness; delamination; finite element; flexbeam AB Nonlinear tapered flexbeam laminates, with significant ply waviness, were cut from a full-size composite rotor hub flexbeam. The specimens were tested under combined axial tension and cyclic bending loads. All of the specimens had wavy plies through the center and near the surfaces (termed marcelled areas), although for some of the specimens the surface marcels were very obvious, and for others they were much smaller. The specimens failed by first developing cracks through the marcels at the surfaces, and then delaminations grew from those cracks, in both directions. Delamination failure occurred in these specimens at significantly shorter fatigue lives than similar specimens without waviness, tested in Ref 2. A 2-D finite-element model was developed which closely approximated the flexbeam geometry, boundary conditions, and loading. In addition, the FE model duplicated the waviness observed in one of the test specimens. The model was analyzed using a geometrically nonlinear rr code. Modifications were made to the original model to reduce the amplitude of the marcels near the surfaces. The analysis was repeated for each modification. Comparisons of the interlaminar normal stresses, a,, in the various models showed that under combined axial-tension and cyclic-bending lending, for marcels of the same aspect ratio, a, stresses increased as the distance along the taper, from thick to thin end, increased. For marcels of the same aspect ratio and at the same X-location along the taper, a, stresses decreased as the distance from the surface into the flexbeam interior increased. A technique was presented for determining the smallest acceptable marcel aspect ratio at various locations in the flexbeam. C1 NASA, Langley Res Ctr, Vehicle Technol Directorate, USA,Res Lab, Hampton, VA 23681 USA. RP Murri, GB (reprint author), NASA, Langley Res Ctr, Vehicle Technol Directorate, USA,Res Lab, MS 188E, Hampton, VA 23681 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2862-2 J9 AM SOC TEST MATER PY 2001 VL 1383 BP 188 EP 209 DI 10.1520/STP14510S PG 22 WC Materials Science, Composites SC Materials Science GA BS14C UT WOS:000168820900010 ER PT S AU Starnes, JH Hilburger, MW Nemeth, MP AF Starnes, JH Hilburger, MW Nemeth, MP BE Grant, P Rousseau, CQ TI The effects of initial imperfections on the buckling of composite cylindrical shells SO COMPOSITE STRUCTURES: THEORY AND PRACTICE SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT Symposium on Composite Structures - Theory and Practice CY MAY 17-18, 1999 CL SEATTLE, WA SP ASTM Comm D 30 DE graphite-epoxy composite shells; buckling of composite shells; effects of imperfections on composite shell buckling; nonlinear analysis of composite shells AB The results of an experimental and analytical study of the effects of initial imperfections on the buckling response of thin unstiffened graphite-epoxy cylindrical shells with and without a cutout, and with three different shell-wall laminates, are presented. Results that identify the individual and combined effects of traditional initial geometric shell-wall imperfections, and nontraditional shell-wall thickness variations, shell-end geometric imperfections, and variations in loads applied to the ends of the shells on the shell buckling and nonlinear responses, are included. The shells have been analyzed with a robust nonlinear finite-element analysis code for shells that accurately accounts for these effects on the buckling and nonlinear responses of the shells. The analysis results generally correlate well with the experimental results. The nonlinear analysis results are also compared with the results from a traditional linear bifurcation buckling analysis that is commonly used for shell design. The results suggest that the nonlinear analysis procedure can be used for determining accurate, high-fidelity, design knockdown factors for shell bucking and collapse. A discussion of how this high-fidelity nonlinear analysis procedure can be used to form the basis for a shell analysis and design approach that addresses some of the critical shell-buckling design criteria and design considerations for composite shell structures is included. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Starnes, JH (reprint author), NASA, Langley Res Ctr, Mail Stop 190, Hampton, VA 23681 USA. NR 11 TC 2 Z9 2 U1 0 U2 1 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2862-2 J9 AM SOC TEST MATER PY 2001 VL 1383 BP 529 EP 550 DI 10.1520/STP14529S PG 22 WC Materials Science, Composites SC Materials Science GA BS14C UT WOS:000168820900029 ER PT J AU Krueger, R O'Brien, TK AF Krueger, R O'Brien, TK TI A shell/3D modeling technique for the analysis of delaminated composite laminates SO COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING LA English DT Article DE composite materials; finite element analysis ID RELEASE RATE DISTRIBUTIONS; CANTILEVER BEAM SPECIMENS; 3-DIMENSIONAL ANALYSIS; FRACTURE-TOUGHNESS; ELEMENTS; CRACK AB A shell/3D modeling technique was developed for which a local three-dimensional solid finite element model is used only in the immediate vicinity of the delamination front. The goal was to combine the accuracy of the full three-dimensional solution with the computational efficiency of a plate or shell finite element model. Multi-point constraints provided a kinematically compatible interface between the local three-dimensional model and the global structural model which has been meshed with plate or shell finite elements. Double cantilever beam (DCB), end notched flexure (ENF), and single leg bending (SLB) specimens were modeled using the shell/3D technique to study the feasibility for pure mode I (DCB), mode II (ENF) and mixed mode I/II (SLB) cases. Mixed mode strain energy release rate distributions were computed across the width of the specimens using the virtual crack closure technique. Specimens with a unidirectional layup and with a multidirectional layup where the delamination is located between two non-zero degree plies were simulated. For a local three-dimensional model, extending to a minimum of about three specimen thicknesses on either side of the delamination front, the results were in good agreement with mixed mode strain energy release rates obtained from computations where the entire specimen had been modeled with solid elements. For large built-up composite structures modeled with plate elements, the shell/SD modeling technique offers a great potential for reducing the model size, since only a relatively small section in the vicinity of the delamination front needs to be modeled with solid elements. Published by Elsevier Science Ltd. C1 NASA, USA, Res Lab, Vehicle Technol Directorate,Langley Res Ctr, Hampton, VA 23681 USA. RP Krueger, R (reprint author), NASA, USA, Res Lab, Vehicle Technol Directorate,Langley Res Ctr, Mail Code 188E, Hampton, VA 23681 USA. RI Krueger, Ronald/G-5356-2015 NR 34 TC 63 Z9 68 U1 3 U2 9 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1359-835X J9 COMPOS PART A-APPL S JI Compos. Pt. A-Appl. Sci. Manuf. PY 2001 VL 32 IS 1 BP 25 EP 44 DI 10.1016/S1359-835X(00)00133-0 PG 20 WC Engineering, Manufacturing; Materials Science, Composites SC Engineering; Materials Science GA 380YT UT WOS:000165735600003 ER PT J AU Bansal, NP Setlock, JA AF Bansal, NP Setlock, JA TI Fabrication of fiber-reinforced celsian matrix composites SO COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING LA English DT Article DE ceramic-matrix composites (CMCs); celsian; mechanical properties AB A method has been developed for the fabrication of small diameter, multifilament tow, fiber-reinforced ceramic matrix composites. Its application has been successfully demonstrated for the Hi-Nicalon/celsian system. Strong and tough celsian matrix composites, reinforced with BN/SiC-coated Hi-Nicalon fibers, have been fabricated by infiltrating the fiber tows with the matrix slurry, winding the rows on a drum, cutting and stacking of the prepreg tapes in the desired orientation, and hot pressing. The monoclinic celsian phase in the matrix was produced in situ, during hot pressing, from the 0.75BaO-0.25Sr0-Al2O3-2SiO(2) mixed precursor synthesized by solid state reaction from metal oxides. Hot pressing resulted in almost fully dense fiber-reinforced composites. The unidirectional composites having similar to 42 vol.% of fibers exhibited graceful failure with extensive fiber pullout in three-point bend tests at room temperature. Values of yield stress and strain were 435 +/- 35 MPa and 0.27 +/- 0.01%, respectively, and ultimate strengths of 900 +/- 60 MPa were observed. Young's modulus of the composites was measured to be 165 +/- 5 GPa. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. Case Western Reserve Univ, Dept Mat Sci & Engn, Cleveland, OH 44106 USA. RP Bansal, NP (reprint author), NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. NR 17 TC 14 Z9 18 U1 0 U2 7 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1359-835X J9 COMPOS PART A-APPL S JI Compos. Pt. A-Appl. Sci. Manuf. PY 2001 VL 32 IS 8 SI SI BP 1021 EP 1029 DI 10.1016/S1359-835X(00)00169-X PG 9 WC Engineering, Manufacturing; Materials Science, Composites SC Engineering; Materials Science GA 454LQ UT WOS:000169974400006 ER PT J AU Bednarcyk, BA Arnold, SM AF Bednarcyk, BA Arnold, SM TI Micromechanics-based deformation and failure prediction for longitudinally reinforced titanium composites SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article DE metal-matrix composite; model; fiber breakage; viscoplasticity; micromechanics ID BUNDLES PROBABILITY MODEL; METAL-MATRIX COMPOSITES; TENSILE-STRENGTH; FIBROUS MATERIALS; FIBER; DAMAGE; CREEP; BEHAVIOR; RUPTURE AB Two models to account for fiber breakage in longitudinally loaded composite materials have been incorporated into NASA Glenn's Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC) (Arnold SM, Bednarcyk BA, Wilt TE, Trowbridge D. MAC/GMC Users Guide: Version 3.0. NASA/TM- 1999-209070, 1999). The first is Curtin's widely used effective fiber breakage model (Curtin WA. Ultimate strengths of fibre-reinforced ceramics and metals. Composites 1993;24(2):98-102; Curtin WA. Theory of mechanical properties of ceramic-matrix composites. J Am Ceram Soc 1991;74(11):2837-45). This model treats all fibers in the composite as one effective fiber whose properties degrade in accordance with the statistical strength distribution of the actual fibers. The second is a new discrete model that considers failure of many individual fibers in a composite repeating unit cell. This model explicitly includes the important feature of local stress unloading in fractured fibers, even as global loading of the composite continues. MAC/GMC was employed to simulate the longitudinal tensile deformation and failure behavior of several silicon-carbide-fiber/titanium-matrix (SiC/Ti) composites using both models. Through comparison with experiment, MAC/GMC, in conjunction with the incorporated fiber breakage models, is shown to be quite realistic and capable of accurate predictions for various temperatures, fiber volume fractions, and fiber diameters. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 47 TC 25 Z9 25 U1 1 U2 9 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PY 2001 VL 61 IS 5 BP 705 EP 729 DI 10.1016/S0266-3538(01)00004-5 PG 25 WC Materials Science, Composites SC Materials Science GA 430JX UT WOS:000168571700008 ER PT J AU Chawla, N Chawla, KK Koopman, M Patel, B Coffin, C Eldridge, JI AF Chawla, N Chawla, KK Koopman, M Patel, B Coffin, C Eldridge, JI TI Thermal-shock behavior of a Nicalon-fiber-reinforced hybrid glass-ceramic composite SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article DE ceramic matrix composites; whisker; thermal shock; damage; fiber cracking ID MATRIX COMPOSITES; CALCIUM ALUMINOSILICATE; BOROSILICATE GLASS; RESISTANCE AB A Nicalon-fiber-reinforced hybrid composite with a matrix of barium magnesium aluminosilicate (BMAS) glass with silicon carbide whiskers was subjected to thermal shock from elevated to ambient temperatures. The combination of SiC whisker and BMAS glass resulted in a hybrid matrix with a lower thermal expansion than that of the fibers, inducing tensile stresses in the fiber upon thermal shock. This stress state resulted in microstructural damage in the form of fiber cracking and cracking along the fiber/matrix interface, as opposed to the conventional matrix cracking which is typically observed in ceramic-matrix composites. Significant damage in the composite was only observed after three thermal shock cycles. Flexural resonance measurements, used to evaluate thermal shock-induced changes in Young's modulus, showed a reduction in modulus that correlated well with the onset of microstructural damage. Finally, fiber push-out tests, performed to evaluate changes in fiber/matrix interface strength after thermal cycling, indicated a slight decrease in interfacial strength, which was attributed to recession of the carbon-rich fiber surface during thermal shock. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 Arizona State Univ, Dept Chem & Mat Engn, Tempe, AZ 85287 USA. Univ Alabama, Dept Mat & Mech Engn, Birmingham, AL 35294 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Chawla, N (reprint author), Arizona State Univ, Dept Chem & Mat Engn, POB 876006, Tempe, AZ 85287 USA. RI Chawla, Nikhilesh/A-3433-2008 OI Chawla, Nikhilesh/0000-0002-4478-8552 NR 31 TC 15 Z9 19 U1 2 U2 9 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PY 2001 VL 61 IS 13 BP 1923 EP 1930 DI 10.1016/S0266-3538(01)00096-3 PG 8 WC Materials Science, Composites SC Materials Science GA 481EZ UT WOS:000171508100012 ER PT J AU Benedikt, B Kumosa, M Predecki, PK Kumosa, L Castelli, MG Sutter, JK AF Benedikt, B Kumosa, M Predecki, PK Kumosa, L Castelli, MG Sutter, JK TI An analysis of residual thermal stresses in a unidirectional graphite/PMR-15 composite based on X-ray diffraction measurements SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article DE residual stresses; X-ray diffraction; unidirectional polymer matrix composite ID INCLUSIONS; MATRIX AB The purpose of this research is to determine residual thermal stresses in a unidirectional graphite-fiberT/PMR-15 polyimide composite by using crystalline inclusions. X-ray diffraction (,XRD) measurements have been made to determine residual stresses in embedded aluminum and silver inclusions placed between the first and second plies of six-ply unidirectional graphite/PMR-15 composite specimens. In the modeling part of this research, residual thermal stresses in unidirectional graphite/polyimide composite plates and in the embedded aluminum and silver inclusions with interlaminar and intralaminar particle distributions have been modeled by using elastic and visco-elastic laminate theories and the Eshelby method. The numerically determined residual stresses in the particles have been subsequently compared to the residual stresses determined from the XRD analysis. It has been shown in this research that the residual stresses in the unidirectional graphite/polyimide composite can be obtained with reasonable accuracy by using the X-ray diffraction technique in conjunction with the application of the visco-elastic Eshelby method of multiple inclusions. The modeling has also shown that the distribution of the aluminum and silver particles and their geometries have a strong effect on the XRD data and the thermal stress analysis based on the concept of embedded crystalline inclusions. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 Univ Denver, Dept Engn, Ctr Adv Mat & Sci, Denver, CO 80208 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Kumosa, M (reprint author), Univ Denver, Dept Engn, Ctr Adv Mat & Sci, 2390 S York St, Denver, CO 80208 USA. NR 23 TC 35 Z9 35 U1 1 U2 13 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PY 2001 VL 61 IS 14 BP 1977 EP 1994 DI 10.1016/S0266-3538(01)00060-4 PG 18 WC Materials Science, Composites SC Materials Science GA 491BX UT WOS:000172089100001 ER PT B AU Chang, SC Wu, YH Wang, XY Yang, V AF Chang, SC Wu, YH Wang, XY Yang, V BE Satofuka, N TI Local mesh refinement in the space-time CE/SE method SO COMPUTATIONAL FLUID DYNAMICS 2000 LA English DT Proceedings Paper CT 1st International Conference on Computational Fluid Dynamics (ICCFD) CY JUL 15-17, 2000 CL KYOTO INST TECHNOL, KYOTO, JAPAN SP Minist Educ, Sci, Sports & Culture, Natl Aerosp Lab, NASA, Commemorat Assoc Japan World Exposit (1970), Kyoto City, Kyoto Prefecture, Japan Soc Computat Fluid Dynam, Japan Soc Aeronaut & Space Sci, Japan Soc Fluid Dynam, Japan Soc Mech Engineers, Japan Soc Computat Engn & Sci, Hewlett Packard Japan Ltd, Ishikawajima Harima Heavy Ind Co Ltd, KGT Inc, NKK Corp, Toray Ind Inc, Towa Corp, Toyota Motor Corp HO KYOTO INST TECHNOL ID CONSERVATION ELEMENT AB A local mesh refinement procedure for the CE/SE method which does not use an iterative procedure in the treatments of grid-to-grid communications is described. It is shown that a refinement ratio in the order of 10 can be applied successfully across a single coarse grid/fine grid interface. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Chang, SC (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-41459-2 PY 2001 BP 61 EP 66 PG 6 WC Mathematics, Applied; Mechanics SC Mathematics; Mechanics GA BT66H UT WOS:000173667000006 ER PT B AU Mavriplis, DJ AF Mavriplis, DJ BE Satofuka, N TI Large-scale parallel unstructured mesh computations using a multigrid approach SO COMPUTATIONAL FLUID DYNAMICS 2000 LA English DT Proceedings Paper CT 1st International Conference on Computational Fluid Dynamics (ICCFD) CY JUL 15-17, 2000 CL KYOTO INST TECHNOL, KYOTO, JAPAN SP Minist Educ, Sci, Sports & Culture, Natl Aerosp Lab, NASA, Commemorat Assoc Japan World Exposit (1970), Kyoto City, Kyoto Prefecture, Japan Soc Computat Fluid Dynam, Japan Soc Aeronaut & Space Sci, Japan Soc Fluid Dynam, Japan Soc Mech Engineers, Japan Soc Computat Engn & Sci, Hewlett Packard Japan Ltd, Ishikawajima Harima Heavy Ind Co Ltd, KGT Inc, NKK Corp, Toray Ind Inc, Towa Corp, Toyota Motor Corp HO KYOTO INST TECHNOL C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Mavriplis, DJ (reprint author), NASA, Langley Res Ctr, ICASE, MS 132C, Hampton, VA 23681 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-41459-2 PY 2001 BP 99 EP 104 PG 6 WC Mathematics, Applied; Mechanics SC Mathematics; Mechanics GA BT66H UT WOS:000173667000012 ER PT B AU Liou, MS Zheng, Y AF Liou, MS Zheng, Y BE Satofuka, N TI A three-dimensional hybrid grid: DRAGON grid SO COMPUTATIONAL FLUID DYNAMICS 2000 LA English DT Proceedings Paper CT 1st International Conference on Computational Fluid Dynamics (ICCFD) CY JUL 15-17, 2000 CL KYOTO INST TECHNOL, KYOTO, JAPAN SP Minist Educ, Sci, Sports & Culture, Natl Aerosp Lab, NASA, Commemorat Assoc Japan World Exposit (1970), Kyoto City, Kyoto Prefecture, Japan Soc Computat Fluid Dynam, Japan Soc Aeronaut & Space Sci, Japan Soc Fluid Dynam, Japan Soc Mech Engineers, Japan Soc Computat Engn & Sci, Hewlett Packard Japan Ltd, Ishikawajima Harima Heavy Ind Co Ltd, KGT Inc, NKK Corp, Toray Ind Inc, Towa Corp, Toyota Motor Corp HO KYOTO INST TECHNOL ID UNSTRUCTURED MESH GENERATION C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Liou, MS (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RI Zheng, Yao/A-3913-2016 NR 10 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-41459-2 PY 2001 BP 113 EP 118 PG 6 WC Mathematics, Applied; Mechanics SC Mathematics; Mechanics GA BT66H UT WOS:000173667000014 ER PT B AU Himansu, A Jorgenson, PCE Wang, XY Chang, SC AF Himansu, A Jorgenson, PCE Wang, XY Chang, SC BE Satofuka, N TI Parallel CE/SE computations via domain decomposition SO COMPUTATIONAL FLUID DYNAMICS 2000 LA English DT Proceedings Paper CT 1st International Conference on Computational Fluid Dynamics (ICCFD) CY JUL 15-17, 2000 CL KYOTO INST TECHNOL, KYOTO, JAPAN SP Minist Educ, Sci, Sports & Culture, Natl Aerosp Lab, NASA, Commemorat Assoc Japan World Exposit (1970), Kyoto City, Kyoto Prefecture, Japan Soc Computat Fluid Dynam, Japan Soc Aeronaut & Space Sci, Japan Soc Fluid Dynam, Japan Soc Mech Engineers, Japan Soc Computat Engn & Sci, Hewlett Packard Japan Ltd, Ishikawajima Harima Heavy Ind Co Ltd, KGT Inc, NKK Corp, Toray Ind Inc, Towa Corp, Toyota Motor Corp HO KYOTO INST TECHNOL ID TIME CONSERVATION ELEMENT AB This paper describes the parallelization strategy and achieved parallel efficiency of an explicit time-marching algorithm for solving conservation laws. The Space-Time Conservation Element and Solution Element (CE/SE) algorithm for solving the 2D and 3D Euler equations is parallelized with the aid of domain decomposition. The parallel efficiency of the resultant algorithm on a Silicon Graphics Origin 2000 parallel computer is checked. C1 NASA, Glenn Res Ctr, Taitech Inc, Cleveland, OH 44135 USA. RP Himansu, A (reprint author), NASA, Glenn Res Ctr, Taitech Inc, Cleveland, OH 44135 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-41459-2 PY 2001 BP 423 EP 428 PG 6 WC Mathematics, Applied; Mechanics SC Mathematics; Mechanics GA BT66H UT WOS:000173667000063 ER PT B AU Wang, XY Chang, SC Jorgenson, P AF Wang, XY Chang, SC Jorgenson, P BE Satofuka, N TI Numerical simulation of aeroacoustic field in a 2D cascade involving a downstream moving grid using the space-time CE/SE method SO COMPUTATIONAL FLUID DYNAMICS 2000 LA English DT Proceedings Paper CT 1st International Conference on Computational Fluid Dynamics (ICCFD) CY JUL 15-17, 2000 CL KYOTO INST TECHNOL, KYOTO, JAPAN SP Minist Educ, Sci, Sports & Culture, Natl Aerosp Lab, NASA, Commemorat Assoc Japan World Exposit (1970), Kyoto City, Kyoto Prefecture, Japan Soc Computat Fluid Dynam, Japan Soc Aeronaut & Space Sci, Japan Soc Fluid Dynam, Japan Soc Mech Engineers, Japan Soc Computat Engn & Sci, Hewlett Packard Japan Ltd, Ishikawajima Harima Heavy Ind Co Ltd, KGT Inc, NKK Corp, Toray Ind Inc, Towa Corp, Toyota Motor Corp HO KYOTO INST TECHNOL ID CONSERVATION ELEMENT AB The space-time conservation element and solution element (CE/SE) method is used to solve an aeroacoustic benchmark problem regarding turbomachinery noise. It concerns the aeroacoustic field generated by the interaction of a convected gust with a 2D cascade of flat-plate airfoils with a downstream moving grid. This tests the accuracy of a numerical method and the ability to model the acoustic wave and the gust across a sliding interface typical of those used in rotor stator interaction problems. The 2D nonlinear Euler Equations are solved and the converged numerical solutions are presented and compared with the corresponding analytical solution. The comparison shows that the CE/SE method is capable of producing accurate solutions in a simple manner. C1 NASA, Gleen Res Ctr, Taitech Inc, Cleveland, OH 44135 USA. RP Wang, XY (reprint author), NASA, Gleen Res Ctr, Taitech Inc, Cleveland, OH 44135 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-41459-2 PY 2001 BP 543 EP 548 PG 6 WC Mathematics, Applied; Mechanics SC Mathematics; Mechanics GA BT66H UT WOS:000173667000082 ER PT B AU Chang, SC Zhang, ZC Yu, STJ Jorgenson, PCE AF Chang, SC Zhang, ZC Yu, STJ Jorgenson, PCE BE Satofuka, N TI A unified wall boundary treatment for viscous and inviscid flows in the CE/SE method SO COMPUTATIONAL FLUID DYNAMICS 2000 LA English DT Proceedings Paper CT 1st International Conference on Computational Fluid Dynamics (ICCFD) CY JUL 15-17, 2000 CL KYOTO INST TECHNOL, KYOTO, JAPAN SP Minist Educ, Sci, Sports & Culture, Natl Aerosp Lab, NASA, Commemorat Assoc Japan World Exposit (1970), Kyoto City, Kyoto Prefecture, Japan Soc Computat Fluid Dynam, Japan Soc Aeronaut & Space Sci, Japan Soc Fluid Dynam, Japan Soc Mech Engineers, Japan Soc Computat Engn & Sci, Hewlett Packard Japan Ltd, Ishikawajima Harima Heavy Ind Co Ltd, KGT Inc, NKK Corp, Toray Ind Inc, Towa Corp, Toyota Motor Corp HO KYOTO INST TECHNOL ID TIME CONSERVATION ELEMENT AB In the setting of the CE/SE method, a new and unified wall boundary treatment for the Navier-Stokes and Euler Equations is proposed. In essence, the shear stress exerted on the fluid by a wall is modeled as a source term as a part of local space-time flux conservation in the vicinity of a wall boundary. When the fluid is inviscid, the source term vanishes and the boundary condition reduces to the usual "slip" condition. On the other hand, when the fluid is viscous, the source-term effect is consistent with the traditional no-slip condition. Numerical results show that the new treatment is robust, efficient and accurate for viscous and inviscid flows. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Chang, SC (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-41459-2 PY 2001 BP 671 EP 676 PG 6 WC Mathematics, Applied; Mechanics SC Mathematics; Mechanics GA BT66H UT WOS:000173667000102 ER PT B AU Yee, HC Sjogreen, B Sandham, ND Hadjadj, A AF Yee, HC Sjogreen, B Sandham, ND Hadjadj, A BE Hafez, M Morinishi, K Periaux, J TI Progress in the development of a class of efficient low dissipative high order shock-capturing methods SO COMPUTATIONAL FLUID DYNAMICS FOR THE 21ST CENTURY, PROCEEDINGS SE NOTES ON NUMERICAL FLUID MECHANICS LA English DT Proceedings Paper CT 1st International Conference on Computational Fluid Dynamics (ICCFD) CY JUL 15-17, 2000 CL KYOTO INST TECHNOL, KYOTO, JAPAN SP Minist Educ, Sci, Sports & Culture, Natl Aerosp Lab, NASA, Commemorat Assoc Japan World Exposit (1970), Kyoto City, Kyoto Prefecture, Japan Soc Computat Fluid Dynam, Japan Soc Aeronaut & Space Sci, Japan Soc Fluid Dynam, Japan Soc Mech Engineers, Japan Soc Computat Engn & Sci, Hewlett Packard Japan Ltd, Ishikawajima Harima Heavy Ind Co Ltd, KGT Inc, NKK Corp, Toray Ind Inc, Towa Corp, Toyota Motor Corp HO KYOTO INST TECHNOL ID CONSERVATION-LAWS; EULER EQUATIONS; DIFFERENCE; RESOLUTION; SUMMATION; ENTROPY; SCHEMES; FLOWS; PARTS AB In a series of papers, Olsson (1994, 1995), Olsson & Oliger (1994), Strand (1994), Gerritsen & Olsson (1996), Yee et al. (1999a,b, 2000) and Sandham & Yee (2000), the issue of nonlinear stability of the compressible Euler and Navier-Stokes Equations, including physical boundaries, and the corresponding development of the discrete analogue of nonlinear stable high order schemes, including boundary schemes, were developed, extended and evaluated for various fluid flows. High order here refers to spatial schemes that are essentially fourth-order or higher away from shock and shear regions. The objective of this paper is to give an overview of the progress of the low dissipative high order shock-capturing schemes proposed by Yee et al. (1999a,b, 2000). This class of schemes consists of simple non-dissipative high order compact or non-compact central spatial differencings and adaptive nonlinear numerical dissipation operators to minimize the use of numerical dissipation. The amount of numerical dissipation is further minimized by applying the scheme to the entropy splitting form of the inviscid flux derivatives, and by rewriting the viscous terms to minimize odd-even decoupling before the application of the central scheme (Sandham & Yee). The efficiency and accuracy of these schemes axe compared with spectral, TVD and fifth-order WENO schemes. A new approach of Sjogreen & Yee (2000) utilizing non-orthogonal multi-resolution wavelet basis functions as sensors to dynamically determine the appropriate amount of numerical dissipation to be added to the non-dissipative high order spatial scheme at each grid point will be discussed. Numerical experiments of long time integration of smooth flows, shock-turbulence interactions, direct numerical simulations of a 3-D compressible turbulent plane channel flow, and various mixing layer problems indicate that these schemes are especially suitable for practical complex problems in nonlinear aeroacoustics, rotorcraft dynamics, direct numerical simulation or large eddy simulation of compressible turbulent flows at various speeds including high-speed shock-turbulence interactions, and general long time wave propagation problems. These schemes, including entropy splitting, have also been extended to freestream preserving schemes on curvilinear moving grids for a thermally perfect gas (Vinokur Yee 2000). C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Yee, HC (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 29 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-42053-3 J9 NOTE NUM FL PY 2001 VL 78 BP 77 EP 102 PG 26 WC Engineering, Aerospace; Computer Science, Theory & Methods; Mathematics, Applied; Mechanics SC Engineering; Computer Science; Mathematics; Mechanics GA BT70L UT WOS:000173805500006 ER PT J AU Papalexandris, MV Milman, MH AF Papalexandris, MV Milman, MH TI Active control and parameter updating techniques for nonlinear thermal network models SO COMPUTATIONAL MECHANICS LA English DT Article AB The present article reports on active control and parameter updating techniques for thermal models based on the network approach. Emphasis is placed on applications where radiation plays a dominant role. Examples of such applications are the thermal design and modeling of spacecrafts and space-based science instruments. Active thermal control of a system aims to approximate a desired temperature distribution or to minimize a suitably defined temperature-dependent functional. Similarly, parameter updating aims to update the values of certain parameters of the thermal model so that the output approximates a distribution obtained through direct measurements. Both problems are formulated as nonlinear, least-square optimization problems. The proposed strategies for their solution are explained in detail and their efficiency is demonstrated through numerical tests. Finally, certain theoretical results pertaining to the characterization of solutions of the problems of interest are also presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Papalexandris, MV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 19 TC 5 Z9 6 U1 1 U2 2 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0178-7675 J9 COMPUT MECH JI Comput. Mech. PD JAN PY 2001 VL 27 IS 1 BP 11 EP 22 DI 10.1007/s004660000209 PG 12 WC Mathematics, Interdisciplinary Applications; Mechanics SC Mathematics; Mechanics GA 401EY UT WOS:000166915400002 ER PT S AU Frumkin, M Jin, HQ Yan, J AF Frumkin, M Jin, HQ Yan, J BE Alexandrov, VN Dongarra, JJ Juliano, BA Renner, RS Tan, CJK TI Automation of data traffic control on DSM architectures SO COMPUTATIONAL SCIENCE -- ICCS 200, PROCEEDINGS PT 2 SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT International Conference on Computational Science (ICCS 2001) CY MAY 28-30, 2001 CL San Francisco, CA AB The distributed shared memory (DSM) architecture simplifies development of parallel programs by relieving a user from the tedious task of distributing data across processors. Furthermore, it allows incremental parallelization using, for example, OpenMP or Java threads. While it is easy to demonstrate good performance on a few processors, achieving good scalability still requires a good understanding of data flow in the application. In this paper we discuss ADAPT, an Automatic Data Alignment and Placement Tool, that detects data congestions in FORTRAN array oriented codes and suggests code transformations to resolve them. We then show how ADAPT suggested transformations, including data blocking, data placement, data transposition and page size control improve performance of the NAS Parallel Benchmarks. C1 NASA, Ames Res Ctr, Numer Aerosp Simulat Syst Div, Moffett Field, CA 94035 USA. RP Frumkin, M (reprint author), NASA, Ames Res Ctr, Numer Aerosp Simulat Syst Div, MS T27 A-2, Moffett Field, CA 94035 USA. EM frumkin@nas.nasa.gov; hjin@nas.nasa.gov; yan@nas.nasa.gov NR 14 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-42233-1 J9 LECT NOTES COMPUT SC PY 2001 VL 2074 BP 771 EP 780 PG 10 WC Computer Science, Artificial Intelligence; Computer Science, Theory & Methods SC Computer Science GA BBQ28 UT WOS:000227039400082 ER PT B AU Hand, C AF Hand, C BE Chung, A TI Neural organization of sensor webs SO COMPUTER APPLICATIONS IN INDUSTRY AND ENGINEERING LA English DT Proceedings Paper CT 14th International Conference on Computer Applications in Industry and Engineering CY NOV 27-29, 2001 CL LAS VEGAS, NV SP Int Soc Comp & Their Applicat DE sensor webs; neural networks AB Sensor webs are an emerging data collection technology that is in need of an organizing schema. Artificial neural networks are a computing paradigm based on the architectures found in biological systems. Nature has been using neural networks to organize and control sensor webs for at least a billion years. This paper gives two examples of how this organization works and suggests a method to apply this established technology to the emerging technology of sensor webs. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hand, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU INTERNATIONAL SOCIETY COMPUTER S & THEIR APPLICATIONS (ISCA) PI RALEIGH PA 8820 SIX FORKS ROAD, RALEIGH, NC 27615 USA BN 1-880843-40-4 PY 2001 BP 19 EP 22 PG 4 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications; Imaging Science & Photographic Technology SC Computer Science; Imaging Science & Photographic Technology GA BV53R UT WOS:000179289400005 ER PT B AU Jeffries, DK Ferguson, F Chandra, S AF Jeffries, DK Ferguson, F Chandra, S BE Chung, A TI Numerical investigation of freestream/exhaust plume interaction SO COMPUTER APPLICATIONS IN INDUSTRY AND ENGINEERING LA English DT Proceedings Paper CT 14th International Conference on Computer Applications in Industry and Engineering CY NOV 27-29, 2001 CL LAS VEGAS, NV SP Int Soc Comp & Their Applicat AB A very competitive atmosphere shrouds the current aerospace market, which includes commercial and military airplanes, missiles and launch vehicles. As a result, designers now must optimize their vehicle's performance while maintaining or even reducing respective costs. However, vehicles operating at a high altitude experience a number of flow phenomena, which typically hamper the vehicle's overall performance. And because the effects of these phenomena are not fully known, designers are generally forced to predict a worst possible case of the phenomenon occurring on their vehicles and design to medicate those effects. The immediate result is a decrease in the vehicle's capabilities and an increase in production cost. Lockheed Martin is currently developing the next generation of Atlas Launch Vehicle, the Atlas V, to compete in this market. And therefore, must strive to maintain the reliability and performance success from the Atlas line of launch vehicles. On board instrumentation and wind tunnel testing on a previous configuration, the Atlas IIIA, indicates that a phenomenon known as Plume Induced Flow Separation (PIFS) is occurring on the Atlas Rocket. PIFS allows the re-circulation of hot thrust gases into regions of separated flow along the vehicle's surface, increasing surface heat transfer rates on the vehicle. Without the ability to perform a complete three-dimensional analysis on the effects of the PIFS phenomenon, Lockheed Martin must default to a worst-case scenario for PIFS in the design of protecting their vehicle. This requires a large portion of the aft section of the vehicle to be covered in thermal protection, increasing the overall weight, while decreasing the overall vehicle capability. The main objective of this research study was to perform a numerical investigation of the PIFS phenomenon occurring on an Atlas IIIA Launch Vehicle. The Numerical simulation of the Atlas IIIA/PIFS flowfield has been performed at a steady-state point along the vehicle's flight path. And the numerical prediction of the occurrence, extent and effects of the phenomenon will be presented to Lockheed Martin to used to possibly optimize the design of their Atlas Launch Vehicle. C1 N Carolina Agr & Tech State Univ, CFD Grp, NASA, CAR, Greensboro, NC 27411 USA. RP Jeffries, DK (reprint author), N Carolina Agr & Tech State Univ, CFD Grp, NASA, CAR, Greensboro, NC 27411 USA. NR 2 TC 0 Z9 0 U1 0 U2 1 PU INTERNATIONAL SOCIETY COMPUTER S & THEIR APPLICATIONS (ISCA) PI RALEIGH PA 8820 SIX FORKS ROAD, RALEIGH, NC 27615 USA BN 1-880843-40-4 PY 2001 BP 89 EP 92 PG 4 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications; Imaging Science & Photographic Technology SC Computer Science; Imaging Science & Photographic Technology GA BV53R UT WOS:000179289400021 ER PT J AU LeBeau, GJ Lumpkin, FE AF LeBeau, GJ Lumpkin, FE TI Application highlights of the DSMC Analysis Code (DAC) software for simulating rarefied flows SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article; Proceedings Paper CT 5th US National Congress on Computational Mechanics CY AUG 04-06, 1999 CL UNIV COLORADO, BOULDER, COLORADO HO UNIV COLORADO ID MONTE-CARLO SIMULATION; ORBITER AB The DSMC Analysis Code (DAC) software represents the National Aeronautics and Space Administration's (NASA's) state-of-the-art implementation of the Direct Simulation Monte Carlo (DSMC) method of Bird for simulating three-dimensional flows. It is utilized by NASA, as well as other organizations from the government, commercial and academic sectors to simulate rarefied gas dynamic environments with complex geometric or flowfield characteristics. The fundamentals of the DSMC method are presented to provide the necessary groundwork for a discussion of the important features of the DAC software. The accuracy of the implementation is demonstrated through a collection of previously documented results, where simulations performed using the DAC software are compared to other codes as well as actual flight derived data. A compilation of diverse applications is used to highlight the software's underlying flexibility and the significance of this capability to support important NASA missions. (C) 2001 Elsevier Science B.V. All rights reserved. C1 NASA, Lyndon B Johnson Space Ctr, Aerosci & Flight Mech Div, Houston, TX 77058 USA. RP LeBeau, GJ (reprint author), NASA, Lyndon B Johnson Space Ctr, Aerosci & Flight Mech Div, Houston, TX 77058 USA. NR 48 TC 35 Z9 40 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PY 2001 VL 191 IS 6-7 BP 595 EP 609 DI 10.1016/S0045-7825(01)00304-8 PG 15 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA 500AK UT WOS:000172603400007 ER PT J AU Leamy, MJ Noor, AK Wasfy, TM AF Leamy, MJ Noor, AK Wasfy, TM TI Dynamic simulation of a tethered satellite system using finite elements and fuzzy sets SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID ELECTRODYNAMIC TETHERS; MULTIBODY SYSTEMS AB Dynamic simulations are performed for the NASA planned propulsive small expendable deployer system (ProSEDS) space tether mission using two finite element analysis codes. The first is a specialized code for simulating tethered space systems. The second is an inhouse flexible multibody dynamics code adapted herein for modeling tethered satellites. The simulation of. the ProSEDS mission is divided into two operations: a tether deployment operation and an electrodynamic operation. The specialized code uses a fixed number of nodes and finite elements in simulating the deployment operation, while the in-house code uses a variable number of nodes and elements. The application of each approach is discussed. A fuzzy-set technique is used in conjunction with the two codes to assess the effect of parameter variations on the deployment and electrodynamic operation of the ProSEDS tether. Detailed numerical simulations reveal that the deployment operation is not sensitive to variations in material parameters, but is sensitive to variations in the initial tether ejection momentum and to controller parameters. The electrodynamic operation is found to be highly sensitive to variations in earth's magnetic field and, to a lesser extent, variations in material and plasma parameters. Published by Elsevier Science B.V. C1 Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA 23681 USA. RP Noor, AK (reprint author), Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Mail Stop 201, Hampton, VA 23681 USA. NR 43 TC 19 Z9 21 U1 2 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PY 2001 VL 190 IS 37-38 BP 4847 EP 4870 DI 10.1016/S0045-7825(00)00352-2 PG 24 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA 449RW UT WOS:000169701800005 ER PT J AU Litvin, FL Fan, Q Vecchiato, D Demenego, A Handschuh, RF Sep, TM AF Litvin, FL Fan, Q Vecchiato, D Demenego, A Handschuh, RF Sep, TM TI Computerized generation and simulation of meshing of modified spur and helical gears manufactured by shaving SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article AB Modification of geometry of spur and helical gears with parallel axes and helical gears with crossed axes is proposed. The finishing process of gear generation is shaving. The purposes of modification of gear geometry are: (i) localization and stabilization of bearing contact, and (ii) reduction of noise and vibration. The goals mentioned above are achieved as follows: 1. The pinion shaver tooth surface, in comparison with a conventional screw involute surface, is profile crowned. 2. Plunging during the process of pinion shaving is provided by variation of shortest distance E between the shaver and pinion axes. Variation of E is executed by application of a parabolic function. 3. The pinion tooth surface becomes double-crowned, in profile and longitudinal directions, due to profile crowning of pinion shaver and variation of plunging. The gear tooth surface is generated as a conventional involute gear. Tooth contact analysis (TCA) computer program for simulation of meshing and contact of shaved pinion-gear tooth surfaces is developed. The developed theory is illustrated with TCA results obtained for spur and helical gears. (C) 2001 Elsevier Science B.V. All rights reserved. C1 Univ Illinois, Dept Mech Engn MC 251, Gear Res Ctr, Engn Res Facil 2039,ERF, Chicago, IL 60607 USA. USA, Res Lab, NASA, J Glenn Res Ctr, Cleveland, OH USA. Visteon Corp, Dearborn, MI USA. RP Litvin, FL (reprint author), Univ Illinois, Dept Mech Engn MC 251, Gear Res Ctr, Engn Res Facil 2039,ERF, 842 W Taylor St, Chicago, IL 60607 USA. NR 6 TC 23 Z9 34 U1 0 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PY 2001 VL 190 IS 39 BP 5037 EP 5055 DI 10.1016/S0045-7825(00)00362-5 PG 19 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA 449RY UT WOS:000169702000001 ER PT J AU Leamy, MJ Noor, AK Wasfy, TM AF Leamy, MJ Noor, AK Wasfy, TM TI Sensitivity analysis of bare-wire space tether systems SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID ELECTRODYNAMIC TETHERS AB Hypergeometric series solutions are presented for the electrodynamic response of bare-wire tether systems, and are used to generate closed-form expressions for the sensitivity coefficients in the generator configuration. For the thruster configuration, the governing equations are in the form of three simultaneous differential equations, which do not allow closed-form solutions for the sensitivity coefficients to be generated, and therefore numerical solutions for the sensitivity coefficients are presented. (C) 2001 Elsevier Science B.V. All rights reserved. C1 Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA 23681 USA. RP Noor, AK (reprint author), Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Mail Stop 201, Hampton, VA 23681 USA. NR 8 TC 4 Z9 4 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PY 2001 VL 190 IS 42 BP 5495 EP 5503 DI 10.1016/S0045-7825(01)00163-3 PG 9 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA 460UL UT WOS:000170326900003 ER PT B AU Hand, C AF Hand, C BE Hung, CC TI An improved autoassociative network for controlling autonomous robots SO COMPUTERS AND THEIR APPLICATIONS LA English DT Proceedings Paper CT 16th International Conference on Computers and Their Applications CY MAR 28-30, 2001 CL SEATTLE, WA SP Int Soc Comp & Their Applicat DE autonomous robots; walking robots; synaptic networks AB One promising approach to neural network controlled robotics is the use of autoassociative networks. These networks learn to move a "sensor and effector" vector through a plausible state-space. This approach is, however, hindered by the intrinsically inefficient nature of autoassociative networks. This paper outlines a novel approach that greatly increases the efficiency and resolution of associative networks, and has other implementation benefits as well. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hand, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU INTERNATIONAL SOCIETY COMPUTER S & THEIR APPLICATIONS (ISCA) PI RALEIGH PA 8820 SIX FORKS ROAD, RALEIGH, NC 27615 USA BN 1-880843-37-4 PY 2001 BP 121 EP 124 PG 4 WC Computer Science, Artificial Intelligence; Computer Science, Cybernetics; Computer Science, Hardware & Architecture; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering SC Computer Science GA BV53P UT WOS:000179289200028 ER PT B AU Dempsey, PJ AF Dempsey, PJ BE Starr, AG Rao, BKN TI Gear damage detection using oil debris analysis SO CONDITION MONITORING AND DIAGNOSTIC ENGINEERING MANAGEMENT LA English DT Proceedings Paper CT 14th International Congress on Condition Monitoring and Diagnostic Engineering Management (COMADEM 2001) CY SEP 04-06, 2001 CL MANCHESTER, ENGLAND SP Manchester Sch Engn, Maintenance Engn Res Grp DE gears; transmissions; oil debris sensor; damage detection; health monitoring; pitting fatigue AB The purpose of this paper was to verify, when using an oil debris sensor, that accumulated mass predicts gear pitting damage and to identify a method to set threshold limits for damaged gears. Oil debris data was collected from 8 experiments with no damage and 8 with pitting damage in the NASA Glenn Spur Gear Fatigue Rig. Oil debris feature analysis was performed on this data. Video images of damage progression were also collected from 6 of the experiments with pitting damage. During each test, data from an oil debris sensor was monitored and recorded for the occurrence of pitting damage. The data measured from the oil debris sensor during experiments with damage and with no damage was used to identify membership functions to build a simple fuzzy logic model. Using fuzzy logic techniques and the oil debris data, threshold limits were defined that discriminate between stages of pitting wear. Results indicate accumulated mass combined with fuzzy logic analysis techniques is a good predictor of pitting damage on spur gears. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Dempsey, PJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 21 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS BN 0-08-044036-3 PY 2001 BP 433 EP 440 DI 10.1016/B978-008044036-1/50050-0 PG 8 WC Acoustics; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Engineering, Mechanical SC Acoustics; Computer Science; Engineering GA BV15F UT WOS:000178000300050 ER PT S AU Kenny, BH Lorenz, RD AF Kenny, BH Lorenz, RD GP IEEE IEEE IEEE TI Stator and rotor flux based deadbeat direct torque control of induction machines SO CONFERENCE RECORD OF THE 2001 IEEE INDUSTRY APPLICATIONS CONFERENCE, VOLS 1-4 SE IEEE INDUSTRY APPLICATIONS SOCIETY ANNUAL MEETING LA English DT Proceedings Paper CT 36th Annual Meeting of the Industry-Application-Society (IAS) CY SEP 30-OCT 04, 2000 CL CHICAGO, IL SP IEEE, Ind Appl Soc ID AC MACHINES; POSITION; VELOCITY AB A new, deadbeat type of direct torque control is proposed, analyzed and experimentally verified in this paper. The control is based on stator and rotor flux as state variables. This choice of state variables allows a graphical representation which is transparent and insightful. The graphical solution shows the effects of realistic considerations such as voltage and current limits. A position and speed sensorless implementation of the control, based on the self-sensing signal injection technique, is also demonstrated experimentally for low speed operation. The paper first develops the new, deadbeat DTC methodology and graphical representation of the new algorithm. It then evaluates feasibility via simulation and experimentally demonstrates performance of the new method with a laboratory prototype including the sensorless methods. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Kenny, BH (reprint author), NASA, Glenn Res Ctr, MS 333-2,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 14 TC 6 Z9 8 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0197-2618 BN 0-7803-7114-3 J9 IEEE IND APPLIC SOC PY 2001 BP 133 EP 139 PG 7 WC Automation & Control Systems; Energy & Fuels; Engineering, Electrical & Electronic SC Automation & Control Systems; Energy & Fuels; Engineering GA BT62U UT WOS:000173561900019 ER PT J AU Shiiba, M Arnaud, SB Tanzawa, H Uzawa, K Yamauchi, M AF Shiiba, M Arnaud, SB Tanzawa, H Uzawa, K Yamauchi, M TI Alterations of collagen matrix in weight-bearing bones during skeletal unloading SO CONNECTIVE TISSUE RESEARCH LA English DT Article DE collagen; post-translational modification; lysine hydroxylation; collagen cross-link; skeletal unloading ID HUMAN LYSYL HYDROXYLASE; CROSS-LINKING; CONNECTIVE-TISSUE; I COLLAGEN; MOLECULAR PACKING; FIBRILS; IMMOBILIZATION; CELLS; LOAD; DIFFERENTIATION AB Skeletal unloading induces loss of bone mineral density in weight-bearing bones. The objectives of this study were to characterize the post-translational modifications of collagen of weight-bearing, bones subjected to hindlimb unloading for 8 weeks. In unloaded bones, tibiae and femurs, while the overall amino acid composition was essentially identical in the unloaded and control tibiae and femurs, the collagen cross-link profile showed significant differences. Two major reducible cross-links (analyzed as dihydroxylysinonorleucine and hydroxylysinonorleucine) were increased in the unloaded bones. In addition, the ratios of the farmer to the latter as well as pyridinoline to deoxypyridinoline were significantly decreased in the unloaded bones indicating a difference in the extent of lysine hydroxylation at the cross-linking sites between these two groups. These results indicate that upon skeletal unloading the relative pool of newly synthesized collagen is increased and it is post-translationally altered. The alteration could be associated with impaired osteoblastic differentiation induced by skeletal unloading that results in a mineralization defect. C1 Univ N Carolina, Dent Res Ctr CB 7455, Chapel Hill, NC 27599 USA. NASA, Ames Res Ctr, Santa Cruz, CA 95064 USA. Chiba Univ, Sch Med, Dept Oral Surg, Chiba 280, Japan. RP Yamauchi, M (reprint author), Univ N Carolina, Dent Res Ctr CB 7455, Chapel Hill, NC 27599 USA. NR 48 TC 10 Z9 10 U1 0 U2 1 PU GORDON BREACH PUBLISHING, TAYLOR & FRANCIS GROUP PI PHILADELPHIA PA 325 CHESTNUT ST, 8TH FL, PHILADELPHIA, PA 19106 USA SN 0300-8207 J9 CONNECT TISSUE RES JI Connect. Tissue Res. PY 2001 VL 42 IS 4 BP 303 EP 311 DI 10.3109/03008200109016844 PG 9 WC Cell Biology; Orthopedics SC Cell Biology; Orthopedics GA 499YT UT WOS:000172599100007 PM 11913774 ER PT B AU Brekke, P AF Brekke, P BE Lopez, RJG Rebolo, R Osorio, MRZ TI Impact of SOHO, TRACE and Yohkoh on solar physics SO COOL STARS, STELLAR SYSTEMS AND THE SUN, PROCEEDINGS SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT 11th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun CY OCT 04-08, 1999 CL PUERTO LA CRUZ, SPAIN SP Spains Minist Educ & Cultura, Univ La Laguna, Cabildo Tenerife, Canaries Local Govt ID DIAGNOSTIC SPECTROMETER CDS; TRANSITION-REGION; MAGNETIC RECONNECTION; EXPLOSIVE EVENTS; SUMER INSTRUMENT; FAR-ULTRAVIOLET; EMISSION-LINES; DOPPLER SHIFTS; CORONAL HOLES; QUIET-SUN AB Recent sophisticated space missions have led to substantial alterations in our picture of the physics of our nearest star. In particular the ESA/NASA Solar and Heliospheric Observatory (SOHO) has provided unique data to explore the Sun from its interior, throughout the hot and dynamic atmosphere, and to probe the solar wind and energetic particles. Analysis of the helioseismology data from SOHO has shed new light on a number of structured and dynamical phenomena in the solar interior, such as the absence of differential rotation in the radiative zone, subsurface zonal and meridian flows, and a possible circumpolar jet. Evidence for an upward transfer of magnetic energy from the Sun's surface toward the corona has been established. The ultraviolet instruments have revealed an extremely dynamic solar atmosphere where plasma flows play an important role. The source regions for the high speed solar wind has been identified and the acceleration profiles of both the slow and fast solar wind have been measured. The Japanese Yohkoh satellite has also contributed significant new knowledge about the Sun, in particular on the nature of solar flares. Coordinated observations with SOHO and Yohkoh, and more recently with TRACE have given us a new view of a very complex Sun. This paper tries to summarize some of the highlights from these missions. C1 NASA, Goddard Space Flight Ctr, ESA, Dept Space Sci, Greenbelt, MD 20771 USA. RP Brekke, P (reprint author), NASA, Goddard Space Flight Ctr, ESA, Dept Space Sci, Greenbelt, MD 20771 USA. NR 69 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-056-0 J9 ASTR SOC P PY 2001 VL 223 BP 311 EP 324 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS48R UT WOS:000170040600028 ER PT S AU Bailin, SC Truszkowsk, W AF Bailin, SC Truszkowsk, W BE Klusch, M Zambonelli, F TI Ontology negotiation as a basis for opportunistic cooperation between intelligent information agents SO COOPERATIVE INFORMATION AGENTS V, PROCEEDINGS SE Lecture Notes in Artificial Intelligence LA English DT Article; Proceedings Paper CT 5th International Workshop on Cooperative Information Agents CY SEP 06-08, 2001 CL MODENA, ITALY SP NASA Goddard Space Flight Ctr, NOKIA Res Ctr, Swiss Life A G, Agent LINK II, European Network Excellence Agcy-Based Comp AB This paper describes an approach to ontology negotiation between agents supporting intelligent information management. Our objective is to increase the opportunities for "strange agents to communicate in solving tasks when they encounter each other on the web. C1 Knowledge Evolut Inc, Washington, DC 20036 USA. NASA, Goddard Space Flight Ctr, Informat Syst Ctr, Greenbelt, MD 20771 USA. RP Bailin, SC (reprint author), Knowledge Evolut Inc, 1050 17th St NW,Suite 520, Washington, DC 20036 USA. EM sbailin@kevol.com; Walt.Truszkowski@gsfc.nasa.gov NR 11 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-42545-4 J9 LECT NOTES ARTIF INT PY 2001 VL 2182 BP 223 EP 228 PG 6 WC Computer Science, Artificial Intelligence SC Computer Science GA BW13M UT WOS:000180978200024 ER PT B AU Ramaty, R Lingenfelter, RE Kozlovsky, B AF Ramaty, R Lingenfelter, RE Kozlovsky, B BE VangioniFlam, E Ferlet, R Lemoine, M TI Issues of LiBeB, oxygen and Fe evolution SO COSMIC EVOLUTION: ON THE OCCASION OF THE 60TH BIRTHDAYS OF JEAN AUDOUZE AND JAMES W TRURAN LA English DT Proceedings Paper CT Symposium on Cosmic Evolution CY NOV 13-17, 2000 CL INST ASTROPHS PARIS, PARIS, FRANCE HO INST ASTROPHS PARIS ID COSMIC-RAYS; ELEMENTS; HALO AB We discuss the highlights of our recent research, specifically the refractory vs. volatile interpretation of the rise of [O/Fe] with decreasing [Fe/H], and the issue of primary vs. secondary evolution of Be. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ramaty, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA PO BOX 128 FARRER RD, SINGAPORE 9128, SINGAPORE BN 981-02-4786-9 PY 2001 BP 133 EP 134 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT45W UT WOS:000173048600032 ER PT S AU Kolb, E AF Kolb, E BE Miller, JB TI A recipe for primordial soup SO COSMIC QUESTIONS SE ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article; Proceedings Paper CT Conference on Cosmic Questions CY APR, 1999 CL WASHINGTON, D.C. SP Dialogue Sci, Ethics & Relig, AAAS Program, John Templeton Fdn, Smithsonian Inst, Off Provost, Sci & Spirit Resources Inc, N Amer Montessori Teachers Assoc DE cosmology; Big Bang; origin of the universe AB If the universe emerged from a state of high temperature and high density, we can study the origin of the universe by recreating those conditions in the laboratory. While we can not reproduce the Big Bang, we can recreate its conditions and study the physical processes responsible for producing the rich and varied universe we observe today. C1 Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Grp, Batavia, IL 60510 USA. RP Kolb, E (reprint author), Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Grp, 209 WH 3W,POB 500, Batavia, IL 60510 USA. NR 1 TC 0 Z9 0 U1 1 U2 4 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 EAST 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 BN 1-57331-346-7 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 2001 VL 950 BP 54 EP 65 PG 12 WC Multidisciplinary Sciences; Philosophy SC Science & Technology - Other Topics; Philosophy GA BT92Q UT WOS:000174462800005 PM 11797763 ER PT S AU Nealson, KH AF Nealson, KH BE Miller, JB TI Searching for life in the universe - Lessons from the Earth SO COSMIC QUESTIONS SE ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article; Proceedings Paper CT Conference on Cosmic Questions CY APR, 1999 CL WASHINGTON, D.C. SP Dialogue Sci, Ethics & Relig, AAAS Program, John Templeton Fdn, Smithsonian Inst, Off Provost, Sci & Spirit Resources Inc, N Amer Montessori Teachers Assoc DE life; Mars; prokaryotes; eukaryotes; biosphere; protists; extremophiles; astrobiology; phylogeny; microbes; diversity ID EVOLUTION; MICROORGANISMS; MICROBIOLOGY; PERSPECTIVE; BACTERIA; OXYGEN; MARS AB Space programs will soon allow us to search for life in situ on Mars and to return samples for analysis. A major focal point is to search for evidence of present or past life in these samples, evidence that, if found, would have far-reaching consequences for both science and religion. A search strategy mill consider the entire gamut of life on our own planet, using that information to frame a search that would recognize life even if it were fundamentally different from that we know on Earth. We discuss here how the lessons learned from the study of life on Earth can be used to allow us to develop a general strategy for the search for life in the Universe. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nealson, KH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 4 Z9 4 U1 2 U2 7 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 EAST 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 BN 1-57331-346-7 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 2001 VL 950 BP 241 EP 258 PG 18 WC Multidisciplinary Sciences; Philosophy SC Science & Technology - Other Topics; Philosophy GA BT92Q UT WOS:000174462800020 PM 11797753 ER PT S AU Frieman, JA AF Frieman, JA BE Durrer, R GarciaBellido, J Shaposhnikov, M TI Probing large-scale structure with galaxy surveys SO COSMOLOGY AND PARTICLE PHYSICS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Cosmology and Particle Physics (CAPP 2000) CY JUL 17-28, 2000 CL VERBIER, SWITZERLAND SP Swiss Natl Sci Fdn, Fdn Herbette, Fdn 450e Anniversaire, Univ Autonoma Madrid, Univ Geneve, Univ Lausanne, Tourist Off Verbier ID CAMPANAS REDSHIFT SURVEY; LYMAN-BREAK GALAXIES; POWER SPECTRUM; DENSITY; CATALOG; Z-SIMILAR-TO-3 AB In recent years, the framework for a plausible theory of large-scale structure formation has emerged: primordial, quasi-scale-invariant perturbations from inflation: which subsequently grow by gravitational instability in a universe with a substantial component of cold dark matter. In the near future, a new generation of galaxy redshift surveys, along with cosmic microwave background missions and other cosmological probes, will test this structure formation paradigm with unprecedented precision. This talk highlights recent progress and expected future developments in our understanding of large-scale structure and in testing the inflationary scenario for its formation. C1 NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Frieman, JA (reprint author), NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, POB 500, Batavia, IL 60510 USA. NR 40 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-986-6 J9 AIP CONF PROC PY 2001 VL 555 BP 201 EP 214 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA BS13G UT WOS:000168778800016 ER PT B AU Ross, RG Johnson, DL Metzger, A Kotsubo, V Evtimov, B Olson, J Nast, T Rawlings, RM AF Ross, RG Johnson, DL Metzger, A Kotsubo, V Evtimov, B Olson, J Nast, T Rawlings, RM BE Ross, RG TI Gamma-ray pulse tube cooler development and testing SO CRYOCOOLERS 11 LA English DT Proceedings Paper CT 11th International Cryocooler Conference CY JUN 20-22, 2000 CL BALL AEROSP & TECHNOLOGIES CORP, KEYSTONE, CO HO BALL AEROSP & TECHNOLOGIES CORP AB For a variety of space-science applications, such as gamma-ray spectroscopy, the introduction of cryogenic cooling via a cryocooler can greatly increase the potential science return by allowing the use of more sensitive and lower noise detectors. At the same time, the performance benefits must be carefully weighed against the implementation cost, any possibility of degraded detector performance associated with the operation of the cryocooler, and the requirement to achieve long life. This paper describes the development, test, and performance of a novel new low-cost, low-noise, high-reliability pulse tube cooler, designed specifically for highly cost-constrained, long-life space missions. The developed cooler marries two technologies: a low-cost high-reliability linear compressor and drive electronics from the 1.75 W tactical Stirling cryocooler of DRS Infrared Technologies (formerly Texas Instruments), and an 80 K pulse tube developed specifically for the compressor by Lockheed Martin ATC. The successful new cooler achieves over 1.6 watts of cooling at 80 K at 23 W/W, and has the advantages of greatly reduced vibration at the coldtip and no life-limiting moving cold elements. To achieve maximum life and low vibration, the compressor incorporates flat flexure springs for piston support and uses two opposing pistons in a head-to-head configuration with linear drive motors. The pulse tube is a compact U-tube configuration for improved integration and is mounted to the compressor in a split configuration with a transfer line. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ross, RG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 1 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-46567-1 PY 2001 BP 155 EP 162 PG 8 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical; Physics, Applied SC Engineering; Thermodynamics; Physics GA BT66F UT WOS:000173666500020 ER PT B AU Whitehouse, PL Nellis, GF Zagarola, MV AF Whitehouse, PL Nellis, GF Zagarola, MV BE Ross, RG TI A flexible turbo-Brayton cryocooler model SO CRYOCOOLERS 11 LA English DT Proceedings Paper CT 11th International Cryocooler Conference CY JUN 20-22, 2000 CL BALL AEROSP & TECHNOLOGIES CORP, KEYSTONE, CO HO BALL AEROSP & TECHNOLOGIES CORP AB Cycle modeling of regenerative cryocoolers has received much attention in the literature over the past decade or so, due in part to the complexity of the gas flow. While having received less attention, recuperative cycle cryocoolers are somewhat easier to model in that the continuous gas flow allows one to avoid the time discretization required by oscillatory flows and look directly at the steady-state behavior. As the maturation of its technology nears, the time is right to model various configurations of a turbo-Brayton cryocooler that may be applicable to program such as the Next Generation Space Telescope (NGST) and Constellation-X. As the design parameters codify for these two programs, a flexible turbo-Brayton cryocooler model is required to evaluate the passive/active cooling trades and will certainly be needed in any follow-on design phase. Presented here is a component-based cycle model written in Mathematica. Separate functions, based on the first and second laws of thermodynamics, are used to model individual physical components. The functions are combined for a particular system configuration and solved simultaneously for the state points and mass flow rate. This approach allows for easy mixing and matching of components for various configurations, two of which are shown here. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Whitehouse, PL (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-46567-1 PY 2001 BP 499 EP 504 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical; Physics, Applied SC Engineering; Thermodynamics; Physics GA BT66F UT WOS:000173666500063 ER PT B AU Paine, CG Bowman, RC Pearson, D Schmelzel, ME Bhandari, P Wade, LA AF Paine, CG Bowman, RC Pearson, D Schmelzel, ME Bhandari, P Wade, LA BE Ross, RG TI PLANCK sorption cooler initial compressor element performance tests SO CRYOCOOLERS 11 LA English DT Proceedings Paper CT 11th International Cryocooler Conference CY JUN 20-22, 2000 CL BALL AEROSP & TECHNOLOGIES CORP, KEYSTONE, CO HO BALL AEROSP & TECHNOLOGIES CORP ID HYDROGEN AB PLANCK is an ESA-led mission to map the cosmic microwave background using bolometric and heterodyne instruments; both instruments require cooling, one to similar to20K, the other to 0.1K. JPL is developing a sorption-based hydrogen cooler to provide 18-20 K cooling to the two instruments. The system mass and power limitations require tradeoffs in thermal design. To demonstrate achievement of an acceptable design, three compressor elements of a flight-like configuration have been built and are undergoing characterization and life tests. The compressor elements utilize a La1.01Ni4.78Sn0.22 alloy for reversible hydrogen storage, resistive heaters, and an aluminum foam matrix for thermal uniformity, all contained within a high-pressure vessel. A gas-gap switch provides adjustable thermal isolation. Initial results indicate that hydriding alloy bulk and surface contamination levels are insignificant, and that reversible storage capability is near theoretical limits. We report on static and dynamic thermal characteristics of the compressor elements, and gas supply characteristics related to operational modes of a cooler. We then indicate what further characterization will be performed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Paine, CG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-46567-1 PY 2001 BP 531 EP 540 PG 10 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical; Physics, Applied SC Engineering; Thermodynamics; Physics GA BT66F UT WOS:000173666500067 ER PT B AU Bhandari, P Prina, M Ahart, M Bowman, RC Wade, LA AF Bhandari, P Prina, M Ahart, M Bowman, RC Wade, LA BE Ross, RG TI Sizing and dynamic performance prediction tools for 20 K hydrogen sorption cryocoolers SO CRYOCOOLERS 11 LA English DT Proceedings Paper CT 11th International Cryocooler Conference CY JUN 20-22, 2000 CL BALL AEROSP & TECHNOLOGIES CORP, KEYSTONE, CO HO BALL AEROSP & TECHNOLOGIES CORP AB Two continuous operation 18 K/20 K sorption coolers are being developed by the Jet Propulsion Laboratory (JPL) as a NASA contribution to the European Space Agency (ESA) Planck mission that is currently planned for a 2007 launch. The individual sorption coolers will each be capable of providing a total of about 200 mW of cooling at 18 K and 1.4 W at 20 K given passive radiative pre-cooling at 50 K. The hydrogen sorption coolers will directly cool the Low Frequency Instrument HEMT amplifiers to approximately 20 K and will also serve to intercept parasities and pre-cool a RAL 4.5 K closed-cycle helium J-T cooler to 18 K for the separate High Frequency Instrument. To design the Planck sorption coolers a general Sizing model and a detailed performance prediction model have been developed. In this paper we describe the underlying relationships that determine the required size of a 18/20K hydrogen sorption cooler, and the approach utilized to model and optimize designs. In addition an initial comparison with the first data on a compressor element test will be presented while experimental data for the rest of the cooler components are not available and will be validated in the near future. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bhandari, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 1 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-46567-1 PY 2001 BP 541 EP 549 PG 9 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical; Physics, Applied SC Engineering; Thermodynamics; Physics GA BT66F UT WOS:000173666500068 ER PT B AU Shirron, P Abbondante, N Canavan, E DiPirro, M Grabowski, M Hirsch, M Jackson, M Panek, J Tuttle, J AF Shirron, P Abbondante, N Canavan, E DiPirro, M Grabowski, M Hirsch, M Jackson, M Panek, J Tuttle, J BE Ross, RG TI A continuous adiabatic demagnetization refrigerator for use with mechanical coolers SO CRYOCOOLERS 11 LA English DT Proceedings Paper CT 11th International Cryocooler Conference CY JUN 20-22, 2000 CL BALL AEROSP & TECHNOLOGIES CORP, KEYSTONE, CO HO BALL AEROSP & TECHNOLOGIES CORP ID RAY AB Sub-kelvin refrigeration is an increasingly vital technology for space missions. Future missions are pushing the development of refrigerators with high cooling power, low operating temperature, and, as always, low mass. In this paper we report on the development of an adiabatic demagnetization refrigerator (ADR) which can produce continuous cooling at temperatures of 50 mK or lower, with a cooling power goal of 10 LW. The design uses multiple stages to cascade heat from a continuously-cooled stage up to a heat sink. The serial arrangement makes it possible to add stages to extend the operating range to lower temperature, or to raise the heat rejection temperature. Compared to conventional single-shot ADRs, this system achieves higher cooling power per unit mass and higher efficiency. The ADR is being designed to operate with a heat sink as warm as 10-12 K to make it compatible with a wide variety of mechanical coolers as part of a versatile, cryogen-free low temperature cooling system. A two-stage system has been constructed and a proof-of-principle demonstration was conducted at 100 mK. Details of the design and test results, as well as the direction of future work, are discussed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Shirron, P (reprint author), NASA, Goddard Space Flight Ctr, Code 552, Greenbelt, MD 20771 USA. NR 10 TC 0 Z9 0 U1 0 U2 2 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-46567-1 PY 2001 BP 587 EP 595 PG 9 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical; Physics, Applied SC Engineering; Thermodynamics; Physics GA BT66F UT WOS:000173666500073 ER PT B AU Ross, RG AF Ross, RG BE Ross, RG TI Cryocooler reliability and redundancy considerations for long-life space missions SO CRYOCOOLERS 11 LA English DT Proceedings Paper CT 11th International Cryocooler Conference CY JUN 20-22, 2000 CL BALL AEROSP & TECHNOLOGIES CORP, KEYSTONE, CO HO BALL AEROSP & TECHNOLOGIES CORP AB One means of achieving high reliability with cryogenic payloads involving cryocoolers is to incorporate redundancy, either in the form of redundant coolers and/or redundant drive electronics. To access the redundant elements, electrical and/or heat switches must also be incorporated. Although the redundant elements protect against a possible failure, the increased system complexity and increased cryogenic load associated with the incorporation also have a negative effect on reliability that must be taken into account. This paper presents an analysis of the reliability advantages and disadvantages of a variety of cryocooler redundancy options, based on their total reliability, mass, and power impact at the cryogenic system level. The paper begins with developing an approach for quantifying the probability of failure of the key subassemblies, such as coolers, electronics, and heat switches, associated with the redundancy; the analysis considers the subassembly's state of development, the complexity and testability of its critical failure mechanisms, and the effect of the total cryogenic load on its reliability. Means are also presented for estimating the total cryogenic load as influenced by the addition of the redundant elements. Finally, the overall system performance (reliability, mass, and power) of the various cryocooler redundancy options is computed using the failure probabilities of the individual elements, and the system interrelationships of the elements. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ross, RG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-46567-1 PY 2001 BP 637 EP 648 PG 12 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical; Physics, Applied SC Engineering; Thermodynamics; Physics GA BT66F UT WOS:000173666500079 ER PT B AU Castles, S Price, KD Glaister, DS Gully, W Reilly, J Nast, T Kotsubo, V AF Castles, S Price, KD Glaister, DS Gully, W Reilly, J Nast, T Kotsubo, V BE Ross, RG TI Space cryocooler contamination lessons learned and recommended control procedures SO CRYOCOOLERS 11 LA English DT Proceedings Paper CT 11th International Cryocooler Conference CY JUN 20-22, 2000 CL BALL AEROSP & TECHNOLOGIES CORP, KEYSTONE, CO HO BALL AEROSP & TECHNOLOGIES CORP AB One of the most important characteristics of a space cryocooler is its reliability over a lifetime, typically in excess of 7 years. While design improvements have reduced the probability of mechanical failure, performance degradation directly traceable to internal contamination has been observed across the industry in significant numbers, both in endurance test units and flight units. Therefore, the risk posed by excessive contamination is still a major concern and should be addressed in a consistent standard throughout industry. This paper first describes the cryocooler contamination problem in general terms and then describes one company's efforts and experiences in addressing and resolving the problems. The general discussion identifies a number of sources of internal contamination, the subsequent degradation and failure mechanisms, and the observed impact to a cryocooler's operational efficiency. The paper suggests some specific contamination prevention procedures and their resultant beneficial impact on cooler performance. The most common and preventable source of contamination is the actual working gas charge, and through a comprehensive charge, purge, and fill procedure, the risk of even long term contamination can be significantly minimized. One major source of unexpected contamination is from the vendor supplied gas bottles. The addition of an in-line getter or cold trap to the fill lines helps reduce such contamination. Internal contamination sources that slowly release volatile gases can also be a problem. This paper also describes the lessons learned during Raytheon's Standard Spacecraft Cryocooler (SSC) and Improved Standard Spacecraft Cryocooler (ISSC) development programs in the area of internal contamination, and the subsequent cryocooler gas sample analysis. The exceptionally impressive results before and after the incorporation of identified changes are presented. Based on the authors' observations, the cryocoolers are much more robust to contamination than expected. Contaminant levels generally have to exceed 100 ppm before noticeable piston-to-cylinder or cold-tip temperature degradation is observed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Castles, S (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 2 TC 0 Z9 4 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-46567-1 PY 2001 BP 649 EP 657 PG 9 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical; Physics, Applied SC Engineering; Thermodynamics; Physics GA BT66F UT WOS:000173666500080 ER PT B AU Salerno, LJ Gaby, J Johnson, R Kittel, P Marquardt, ED AF Salerno, LJ Gaby, J Johnson, R Kittel, P Marquardt, ED BE Ross, RG TI Terrestrial applications of zero-boil-off cryogen storage SO CRYOCOOLERS 11 LA English DT Proceedings Paper CT 11th International Cryocooler Conference CY JUN 20-22, 2000 CL BALL AEROSP & TECHNOLOGIES CORP, KEYSTONE, CO HO BALL AEROSP & TECHNOLOGIES CORP AB Storing cryogenic propellants with zero boil off (ZBO) using a combination of active (cryocoolers) and passive technologies has recently received a great deal of attention for long-term space missions. This paper will examine a variety of potential near-term terrestrial applications for ZBO and, where appropriate, provide a rough order of magnitude cost benefit of implementing ZBO technology. NASA's Space Shuttle power system uses supercritical propellant tanks, which are filled several days before launch. If the launch does not occur within 48-96 hours, the tanks must be drained and refilled, further delaying the launch. By implementing ZBO, boil off could be reduced and pad hold time extended by a factor of eight. At NASA's John F. Kennedy Space Center, vented liquid hydrogen (LH2) storage dewars lose 650 kg (500 gal)/day through boiloff. Implementing ZBO would eliminate this, saving $625,000 per year. Overland trucking of LH2 from the supplier to the launch site via roadable dewars results in a cryogen loss of 10% per tanker (1300 kg (1000 gal)/tanker). If this loss could be eliminated, the savings would be approximately $30,000 per year. Within the superconductivity community, there is skepticism about using coolers, based upon reliability concerns. One approach would be to design a hybrid system including a smaller dewar to hold the cryogen for a short time (approx 1 month) and a cooler sized for continuously re-liquefying the boil off. This approach would provide a system with both the high reliability of a stored cryogen combined with the low maintenance and small size of a commercial cryocooler, and could greatly benefit not only high temperature superconducting power applications, but cellular phone base stations or any commercial application that cannot afford a system failure. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Salerno, LJ (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-46567-1 PY 2001 BP 809 EP 816 PG 8 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical; Physics, Applied SC Engineering; Thermodynamics; Physics GA BT66F UT WOS:000173666500098 ER PT J AU Kundrot, CE Judge, RA Pusey, ML Snell, EH AF Kundrot, CE Judge, RA Pusey, ML Snell, EH TI Microgravity and macromolecular crystallography SO CRYSTAL GROWTH & DESIGN LA English DT Review ID PROTEIN CRYSTAL-GROWTH; TETRAGONAL LYSOZYME CRYSTALS; CCD VIDEO OBSERVATION; MIR SPACE STATION; CRYSTALLIZATION APPARATUS; BIOLOGICAL MACROMOLECULES; BACTERIOPHAGE-LAMBDA; APOCRUSTACYANIN C-1; ANGSTROM RESOLUTION; FACILITIES AB Macromolecular crystal growth is seen as an ideal experiment to make use of the reduced acceleration environment provided by an orbiting spacecraft. The experiments are small, are simply operated, and have a high potential scientific and economic impact. In this review we examine the theoretical reasons why microgravity is a beneficial environment for crystal growth and survey the history of experiments on the Space Shuttle Orbiter, on unmanned spacecraft, and on the Mir space station. The results of microgravity crystal growth are considerable when one realizes that the comparisons are always between few microgravity-based experiments and a large number of earth-based experiments. Finally, we outline the direction for optimizing the future use of orbiting platforms. C1 NASA, Marshall Space Flight Ctr, Biotechnol Sci Grp, Huntsville, AL 35812 USA. RP Kundrot, CE (reprint author), NASA, Marshall Space Flight Ctr, Biotechnol Sci Grp, Mail Code SD48, Huntsville, AL 35812 USA. NR 74 TC 83 Z9 91 U1 3 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1528-7483 J9 CRYST GROWTH DES JI Cryst. Growth Des. PD JAN-FEB PY 2001 VL 1 IS 1 BP 87 EP 99 DI 10.1021/cg005511b PG 13 WC Chemistry, Multidisciplinary; Crystallography; Materials Science, Multidisciplinary SC Chemistry; Crystallography; Materials Science GA 519CH UT WOS:000173707000012 ER PT S AU Mouroulis, P Shea, JJ Thomas, DA AF Mouroulis, P Shea, JJ Thomas, DA BE Fischer, RE Johnson, RB Smith, WJ TI Design, tolerancing and alignment of pushbroom imaging spectrometers for high response uniformity SO CURRENT DEVELOPMENTS IN LENS DESIGN AND OPTICAL ENGINEERING II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Current Developments in Lens Design and Optical Engineering II CY JUL 30, 2001 CL SAN DIEGO, CA SP SPIE AB We present a design and tolerancing approach that permits the achievement of a high degree of spatial and spectral uniformity of response from a pushbroom imaging spectrometer. Such uniformity of response is crucial for the extraction of accurate spectroscopic information from remotely sensed data. The spectrometer system example comprises two independent spectrometer modules covering the 400-2500 nm range, separated through a dichroic mirror. The relative merits of alternative approaches are briefly reviewed before concentrating on the problem of building a flight-worthy system that can approximate its design performance. The tolerancing approach requires simultaneous monitoring of many parameters, and specifically: overall image quality, spectral distortion, spectral MTF variation with field, spatial distortion, spatial MTF variation with wavelength, and slit magnification to within a small fraction of a pixel. It is shown that the wavefront error alone or even supplemented by distortion figures is insufficient for characterizing a system with high response uniformity. Tolerance values on the components and their positioning are primarily guided by the need to achieve the same magnification between the two spectrometer modules, as well as by the interferometric alignment method. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91109 USA. RP Mouroulis, P (reprint author), CALTECH, Jet Propuls Lab, 4800 Oak Grove Dr,MS 306-336, Pasadena, CA 91109 USA. NR 6 TC 5 Z9 5 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4155-4 J9 P SOC PHOTO-OPT INS PY 2001 VL 4441 BP 106 EP 117 DI 10.1117/12.449557 PG 12 WC Optics SC Optics GA BT88Y UT WOS:000174363500013 ER PT S AU Boucarut, RA Quijada, MA Lupie, OL Struss, S Miner, L AF Boucarut, RA Quijada, MA Lupie, OL Struss, S Miner, L BE Fischer, RE Johnson, RB Smith, WJ TI Characterization of infrared filters for the Wide Field Camera 3 of Hubble Space Telescope SO CURRENT DEVELOPMENTS IN LENS DESIGN AND OPTICAL ENGINEERING II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Current Developments in Lens Design and Optical Engineering II CY JUL 30, 2001 CL SAN DIEGO, CA SP SPIE DE Hubble Space Telescope; Wide Field Camera 3; cryogenic; space flight optics; band-pass filters; infrared; transmittance AB The Wide Field Camera 3 (WFC3) is a panchromatic imager that will lye deployed in the Hubble Space Telescope (HST) in 2004. The mission of the WFC3 is to enhance HST's imaging capability in the ultraviolet, visible and near-infrared spectral regions. Together with a wavelength coverage spanning 2000A to 1.7 microns, the WFC3 high sensitivity, high spatial resolution, and large field-of-view provide the astronomer with an unprecedented set of tools for exploring all types of exciting astrophysical terrain and for addressing many key questions in astronomy today. The filter compliment, which includes broad, medium, and narrow band filters, naturally reflects the diversity of astronomical programs to be targeted with WFC3. The WFC3 holds 61 UVIS filters elements, 14 IR filters, and 3 dispersive elements. Accurate and comprehensive knowledge of the optical performance of these components including its pass-band and out-of-band rejection behavior are necessary to verify that the instrument will meet its scientific objectives. The measured throughput curves are essential components in instrument performance models used to plan observations, and in calibration algorithms for removing the instrument signature from in-flight data. We will report on the normal incidence in-band and out-of-band transmittance of the IR filters measured near the operating temperature of -30degrees C and additional tests used to characterizes the filter's performance. Details of the characterization apparatus, that include an optical cryostat, and a grating spectrometer are discussed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Boucarut, RA (reprint author), NASA, Goddard Space Flight Ctr, Code 551, Greenbelt, MD 20771 USA. NR 6 TC 2 Z9 2 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4155-4 J9 P SOC PHOTO-OPT INS PY 2001 VL 4441 BP 142 EP 153 DI 10.1117/12.449560 PG 12 WC Optics SC Optics GA BT88Y UT WOS:000174363500016 ER PT J AU Thomas, RA Krishan, A Robinson, DM Sams, C Costa, F AF Thomas, RA Krishan, A Robinson, DM Sams, C Costa, F TI NASA/American Cancer Society high-resolution flow cytometry project-I SO CYTOMETRY LA English DT Article DE flow cytometry; electronic nuclear volume; nuclear packing efficiency; NASA/American Cancer Society; inflight cytometer; DNA; forward scatter ID DNA CONTENT; CYTOFLUOROMETRY AB Background: The NASA/American Cancer Society (ACS) now cytometer can simultaneously analyze the electronic nuclear volume (ENV) and DNA content of cells. This study describes the schematics, resolution, reproducibility, and sensitivity of biological standards analyzed on this unit. Methods: Calibrated beads and biological standards (lymphocytes, trout erythrocytes [TRBC], calf thymocytes, and tumor cells) were analyzed for ENV versus DNA content. Parallel data (forward scatter versus DNA) from a conventional now cytometer were obtained. Results: ENV linearity studies yielded an R value of 0.999. TRBC had a coefficient of variation (CV) of 1.18 +/- 0.13. DNA indexes as low as 1.02 were detectable. DNA con tent of lymphocytes from 42 females was 1.9% greater than that for 60 males, with a noninstrumental variability in total DNA content of 0.5%. The ENV/DNA ratio was constant in 15 normal human tissue samples, but differed in the four animal species tested. The ENV/DNA ratio for a hypodiploid breast carcinoma was 2.3 times greater than that for normal breast tissue. Conclusions: The high-resolution ENV versus DNA analyses are highly reliable, sensitive, and can be used for the detection of near-diploid tumor cells that are difficult to identify with conventional cytometers. ENV/DNA ratio may be a useful parameter for detection of aneuploid populations. Cytometry 43:2-11, 2001. Published 2001 Wiley-Liss, Inc.dagger C1 RATCOM Inc, Miami, FL 33193 USA. Univ Miami, Sch Med, Dept Radiat Oncol, Div Expt Therapeut, Miami, FL USA. St Lukes Hosp Kansas City, Dept Surg, Kansas City, KS USA. NASA, Lyndon B Johnson Space Ctr, Technol Utilizat Off, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Div Med Sci, Houston, TX 77058 USA. Italian Red Cross, Cent Lab, Immunoassay Dept, Rome, Italy. RP Thomas, RA (reprint author), RATCOM Inc, 7620 SW 147 Court, Miami, FL 33193 USA. NR 21 TC 23 Z9 23 U1 0 U2 0 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0196-4763 J9 CYTOMETRY JI Cytometry PD JAN 1 PY 2001 VL 43 IS 1 BP 2 EP 11 DI 10.1002/1097-0320(20010101)43:1<2::AID-CYTO1012>3.0.CO;2-J PG 10 WC Biochemical Research Methods; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 389NL UT WOS:000166244600002 PM 11122478 ER PT S AU Burl, MC AF Burl, MC BE Grossman, RL Kamath, C Kegelmeyer, P Kumar, V Namburu, RR TI Mining large image collections SO DATA MINING FOR SCIENTIFIC AND ENGINEERING APPLICATIONS SE MASSIVE COMPUTING LA English DT Proceedings Paper CT Workshop on Mining Scientific Datasets CY JUL, 2000 CL MINNEAPOLIS, MN SP Army High Performance Comp Res Ctr DE Diamond Eye; image mining; recognition; discovery; query-by-content ID VISUAL-ATTENTION; SPATIAL FILTERS; MODEL; RECOGNITION; PERFORMANCE; INSPECTION; RETRIEVAL; MAGELLAN; VISION AB NASA has been involved with remote exploration of the solar system for over forty years and, as a result, has accumulated a vast archive of images. Continued improvements in acquisition and storage technology are yielding new image sets with data volumes measured in terabytes. Within these large image collections there is a wealth of scientific information, but getting from the data to knowledge is a difficult problem both due to the size of the datasets involved and the difficulty of automatically interpreting image data This chapter provides an overview of our efforts to develop algorithms for mining useful information from large image collections. C1 CALTECH, Jet Prop Lab, Machine Learning Syst Grp, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Machine Learning Syst Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Michael.C.Burl@jpl.nasa.gov NR 53 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 1569-2698 BN 1-4020-0033-2 J9 MASSIVE COMP PY 2001 VL 2 BP 63 EP 84 PG 22 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Computer Science GA BT35B UT WOS:000172716000004 ER PT S AU Lynnes, C Mack, R AF Lynnes, C Mack, R BE Grossman, RL Kamath, C Kegelmeyer, P Kumar, V Namburu, RR TI KDD services at the Goddard Earth Sciences Distributed Active Archive Center SO DATA MINING FOR SCIENTIFIC AND ENGINEERING APPLICATIONS SE MASSIVE COMPUTING LA English DT Proceedings Paper CT Workshop on Mining Scientific Datasets CY JUL, 2000 CL MINNEAPOLIS, MN SP Army High Performance Comp Res Ctr DE KDD Services; data center ID FIRES AB NASA's Goddard Earth Sciences Distributed Active Archive Center (GES DAAC) processes, stores and distributes earth science data from a variety of remote sensing satellites. End users of the data range from instrument scientists to global change and climate researchers to federal agencies and foreign governments. Many of these users apply Knowledge Discovery from Databases (KDD) techniques to large volumes of data (on the order of a terabyte) received from the GES DAAC. However, rapid advances in computer power are enabling increases in data processing that are outpacing tape drive performance and network capacity. As a result, the proportion of data that can be distributed to users continues to decrease. As mitigation, we are migrating more knowledge extraction (e.g., data mining and data reduction) activities into the data center in order to reduce the data volume that needs to be distributed and to offer the users a more useful and manageable product. This migration of activities faces several technical and human-factor challenges. As data reduction and mining algorithms are often quite specific to the user's research needs, the user's algorithm must be integrated virtually unchanged into the archive environment. Also, the archive itself is busy with everyday data archive and distribution activities and cannot be dedicated to, or even impacted by, the mining activities. Therefore, we schedule KDD "campaigns", during which we schedule a wholesale retrieval of specific data products, offering users the opportunity to extract information from the data being retrieved during the campaign. C1 NASA, Goddard Space Flight Ctr, Goddard Earth Sci Distributed Act Arch Ctr, Greenbelt, MD 20771 USA. RP Lynnes, C (reprint author), NASA, Goddard Space Flight Ctr, Goddard Earth Sci Distributed Act Arch Ctr, Greenbelt, MD 20771 USA. RI Lynnes, Christopher/B-4506-2010 OI Lynnes, Christopher/0000-0001-6744-3349 NR 11 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 1569-2698 BN 1-4020-0033-2 J9 MASSIVE COMP PY 2001 VL 2 BP 165 EP 181 PG 17 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Computer Science GA BT35B UT WOS:000172716000010 ER PT S AU Kiely, A Klimesh, M AF Kiely, A Klimesh, M BE Storer, JA Cohn, M TI An adaptable binary entropy coder SO DCC 2001: DATA COMPRESSION CONFERENCE, PROCEEDINGS SE IEEE Data Compression Conference LA English DT Proceedings Paper CT Data Compression Conference (DCC 2001) CY MAR 27-29, 2001 CL SNOWBIRD, UT SP Brandeis Univ, IEEE Comp Soc, Tech Comm Comp Commun AB We present a novel entropy coding technique which is based on recursive interleaving of variable-to-variable length binary source codes. The encoding is adaptable in that each bit to be encoded may have an associated probability estimate which depends on previously encoded bits. The technique may have advantages over arithmetic coding. The technique can achieve arbitrarily small redundancy, and admits a simple and fast decoder. We discuss code design and performance estimation methods, as well as practical encoding and decoding algorithms. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 238-420, Pasadena, CA 91109 USA. EM aaron@shannon.jpl.nasa.gov; klimesh@shannon.jpl.nasa.gov NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1068-0314 BN 0-7695-1031-0 J9 IEEE DATA COMPR CONF PY 2001 BP 391 EP 400 PG 10 WC Computer Science, Information Systems SC Computer Science GA BS19G UT WOS:000169016300040 ER PT B AU Stern, D Connolly, A Eisenhardt, P Elston, R Holden, B Rosati, P Stanford, SA Spinrad, H Tozzi, P Wu, K AF Stern, D Connolly, A Eisenhardt, P Elston, R Holden, B Rosati, P Stanford, SA Spinrad, H Tozzi, P Wu, K BE Cristiani, S Renzini, A Williams, RE TI First results from the SPICES survey SO DEEP FIELDS SE ESO ASTROPHYSICS SYMPOSIA LA English DT Proceedings Paper CT ESO Workshop on Deep Fields CY OCT 09-12, 2000 CL GARCHING, GERMANY SP European SO Observ ID ULTRAVIOLET LUMINOSITY DENSITY; LYMAN-BREAK GALAXIES; HUBBLE DEEP FIELD; HIGH-REDSHIFT; EVOLUTION; SPECTROSCOPY AB We present first results from SPICES, the Spectroscopic, Photometric, Infrared-Chosen Extragalactic Survey. SPICES is comprised of four approximate to 30 arcmin(2) high Galactic latitude fields with deep BRIzJK(5) imaging reaching depths of approximate to 25 mag (AB) in the optical and P 23 mag (AB) in the near-infrared. To date we have 626 spectroscopic redshifts for infrared-selected SPICES sources with K < 20 (Vega). The project is poised to address galaxy formation and evolution to redshift z approximate to 2. We discuss initial results from the survey, including the surface density of extremely red objects and the fraction of infrared sources at z > 1. One of the SPICES fields has been the target of a deep 190 ksec Chandra exposure; we discuss initial results from analysis of that data set. Finally, we briefly discuss a successful campaign to identify high-redshift sources in the SPICES fields. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Stern, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 169-327, Pasadena, CA 91109 USA. NR 17 TC 5 Z9 5 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-42799-6 J9 ESO ASTROPHY SYMP PY 2001 BP 76 EP 80 DI 10.1007/10854354_14 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT83C UT WOS:000174168300014 ER PT B AU Eisenhardt, P Fazio, G Ashby, M Forrest, W Hora, J Huang, J Huchra, J Moseley, H Pahre, M Pipher, J Reach, W Stauffer, J Tollestrup, E Wang, Z Willner, S Wright, E AF Eisenhardt, P Fazio, G Ashby, M Forrest, W Hora, J Huang, J Huchra, J Moseley, H Pahre, M Pipher, J Reach, W Stauffer, J Tollestrup, E Wang, Z Willner, S Wright, E BE Cristiani, S Renzini, A Williams, RE TI Deep surveys with SIRTF's Infrared Array Camera SO DEEP FIELDS SE ESO ASTROPHYSICS SYMPOSIA LA English DT Proceedings Paper CT ESO Workshop on Deep Fields CY OCT 09-12, 2000 CL GARCHING, GERMANY SP European SO Observ AB The Infrared Array Camera (IRAC) on NASA's Space Infrared Telescope Facility (SIRTF) will provide imaging at 3.6, 4.6, 5.8 and 8 pm. The four bands are imaged simultaneously in two adjacent 5 arcminute fields with 1.2" pixels. The expected point source sensitivities in the four bands are 3, 4, 17, and 24 muJy (5sigma in 200 seconds) for objects well away from the ecliptic. SIRTF's angular resolution will be diffraction limited for A > 6.5mum; lambda/D = 0.2" for A in mum and SIRTF's 85 cm primary mirror. SIRTF Guaranteed Time Observers (GTO's) have specified field surveys to be carried out with IRAC with integration times per position ranging from 90 to over 10,000 seconds. I describe the plans for these surveys and their application to the study of galaxy formation and evolution. For further information about SIRTF, see http://sirtf.caltech.edu. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Eisenhardt, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 169-327, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-42799-6 J9 ESO ASTROPHY SYMP PY 2001 BP 154 EP 154 DI 10.1007/10854354_33 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT83C UT WOS:000174168300033 ER PT J AU Barber, RT Marra, J Bidigare, RC Codispoti, LA Halpern, D Johnson, Z Latasa, M Goericke, R Smith, SL AF Barber, RT Marra, J Bidigare, RC Codispoti, LA Halpern, D Johnson, Z Latasa, M Goericke, R Smith, SL TI Primary productivity and its regulation in the Arabian Sea during 1995 SO DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY LA English DT Review ID PARTICULATE ORGANIC-CARBON; NORTHWESTERN INDIAN-OCEAN; EQUATORIAL PACIFIC-OCEAN; NET COMMUNITY PRODUCTION; NORTH-ATLANTIC OCEAN; ZONE COLOR SCANNER; SOUTHWEST MONSOON; COASTAL ZONE; US-JGOFS; PHYTOPLANKTON CHLOROPHYLL AB The annual cycle of monsoon-driven variability in primary productivity was studied in 1995 during the Arabian Sea Expedition as part of the United States Joint Global Ocean Flux Studies (US JGOFS). This paper describes the seasonal progression of productivity and its regulation on a section which ran from the coast of Oman to about 1000km offshore in the central Arabian Sea at 65 degreesE. During the SW Monsoon (June-mid-September), the coolest water and highest nutrient concentrations were close to the coast, although they extended offshore to about 800 km; during the January NE Monsoon, deep convective mixing provided nutrients to the mixed layer in the region 400 - 1000km offshore. As expected, the SW Monsoon was the most productive season (123 +/- 9 mmol Cm(-2) d(-1)) along the southern US JGOFS section from the coast to 1000km offshore, but productivity in the NE Monsoon was surprisingly high (112 +/- 7mmol Cm(-2) d(-1)). There was no onshore/offshore gradient in primary productivity from 150 to 1000km off the Omani coast in 1995, and there was no evidence of light limitation of either primary productivity or photosynthetic performance (P(opt)(B)) from deep convective mixing during the NE Monsoon, deep wind mixing during the SW Monsoon or offshore Ekman downwelling during the SW Monsoon. Productivity during the Spring Intermonsoon (86 +/- 6 mmol Cm(-2) d(-1)) was much higher than in oligotrophic regions such as the tropical Pacific Ocean (29 +/- 2 mmol Cm(-2) d(-1)) or the North Pacific gyre region (32 +/- 8 mmol Cm(-2) d(-1)).The 1995 annual mean productivity (111 +/- 11mmol Cm(-2) d(-1)) along this section from the Omani coast to the central Arabian Sea was about equal to the spring bloom maximum (107 +/- 23 mmol Cm(-2) d(-1)) during the 1989 North Atlantic Bloom Experiment (NABE) and the equatorial, 1 degreesN-1 degreesS wave guide maximum (95 +/- 6mmol Cm(-2) d(-1)) in the Pacific Ocean during the 1992 EqPac study. The 1995 SW Monsoon primary productivity was similar to the mean value observed in the same region in 1994 by the Arabesque Expedition (127 +/- 14 mmol Cm(-2) d(-1)) and in 1964 by the ANTON BRUUN Expedition (115 +/- 27 mmol Cm(-2) d(-1)). During the 1995 SW Monsoon, strong, narrow and meandering current filaments extended from the region of coastal upwelling to about 700km offshore; these filaments had levels of biomass, primary productivity, chlorophyll-specific productivity and diatom abundance that were elevated relative to other locations during the SW Monsoon. The SW Monsoon was the most productive period, but SW Monsoon primary productivity values were lower than predicted because efficient grazing by mesozooplankton kept diatoms from accumulating the biomass necessary for achieving the high levels of primary productivity characteristic of other coastal upwelling regions. The high rates of chlorophyll-specific productivity (P(opt)(B) > 10 mmol C mg Chl(-1) d(-1)) observed in the 1995 SW Monsoon, together with the observed dust flux and iron concentrations, indicate that the Arabian Sea was more iron replete than the equatorial Pacific Ocean or the Southern Ocean. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 Duke Univ, Nicholas Sch Environm, Beaufort, NC 28516 USA. Lamont Doherty Earth Observ, Palisades, NY 10964 USA. Univ Hawaii, Honolulu, HI 96822 USA. Univ Maryland, Horn Point Environm Lab, Cambridge, MD 21613 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Inst Ciencias Mar, E-08039 Barcelona, Spain. Scripps Inst Oceanog, La Jolla, CA 92093 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. RP Barber, RT (reprint author), Duke Univ, Nicholas Sch Environm, Beaufort, NC 28516 USA. EM rbarber@duke.edu RI Johnson, Zackary/E-4601-2011; Latasa, Mikel/D-2202-2011 OI Johnson, Zackary/0000-0003-0793-8512; Latasa, Mikel/0000-0002-8202-0923 NR 150 TC 116 Z9 118 U1 2 U2 21 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0645 J9 DEEP-SEA RES PT II JI Deep-Sea Res. Part II-Top. Stud. Oceanogr. PY 2001 VL 48 IS 6-7 BP 1127 EP 1172 DI 10.1016/S0967-0645(00)00134-X PG 46 WC Oceanography SC Oceanography GA 414JL UT WOS:000167663200004 ER PT J AU Dutkiewicz, S Follows, M Marshall, J Gregg, WW AF Dutkiewicz, S Follows, M Marshall, J Gregg, WW TI Interannual variability of phytoplankton abundances in the North Atlantic SO DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY LA English DT Article ID GENERAL-CIRCULATION-MODEL; SPRING BLOOM; ORGANIC-CARBON; SARGASSO SEA; TIME-SERIES; OCEAN; NITROGEN; PACIFIC; FORMULATION; SIMULATION AB A framework is developed for examining spatial patterns of interannual variability in springtime chlorophyll concentrations as a response to physical changes. A simplified, two-layer bio-physical model reveals regional responses to interannual variability of convective mixing. Vertical mixing can promote productivity in the surface waters through enhanced nutrient supply, but also can retard productivity due to the transport of phytoplankton below Sverdrup's critical depth. The balance of these processes determines the regimes of response in the two-layer model. The regimes may be identified by the ratio of the thickness of Sverdrup's critical layer during spring and the end of winter mixed layer, h(c)/h(m). The responses predicted by the simplified model are found in a more sophisticated four-compartment, nitrogen-based ecosystem model, driven by a general circulation model of the North Atlantic. Anomalously strong convective mixing leads to enhanced chlorophyll concentrations in regions of shallow mixed layers (h(c)/h(m) similar to 1), such as the subtropics. In contrast, in the subpolar regions, where mixed layers are deeper (h(c)/h(m) much less than 1), the sensitivity to convective mixing is weaker, and increased mixing can lead to lower phytoplankton abundances. The numerical model also reveals regions of more complex behavior, such as the inter-gyre boundary, where advective supply of nutrients plays a significant role on interannual timescales. Preliminary analyses of in situ and remote observations from the Bermuda Atlantic Time-Series, Ocean Weather Station "India" and the Coastal Zone Color Scanner also show qualitative agreement. The conceptual framework provides a tool for the analysis of ongoing remote ocean-color observations. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Dutkiewicz, S (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, 54-1511,Massachusetts Ave, Cambridge, MA 02139 USA. RI Follows, Michael/G-9824-2011 NR 45 TC 83 Z9 83 U1 1 U2 26 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0645 J9 DEEP-SEA RES PT II JI Deep-Sea Res. Part II-Top. Stud. Oceanogr. PY 2001 VL 48 IS 10 BP 2323 EP 2344 DI 10.1016/S0967-0645(00)00178-8 PG 22 WC Oceanography SC Oceanography GA 439EQ UT WOS:000169098200009 ER PT J AU Yuan, JC Shiller, AM AF Yuan, JC Shiller, AM TI The distribution of hydrogen peroxide in the Southern and central Atlantic Ocean SO DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY LA English DT Article ID MIXED-LAYER PHOTOCHEMISTRY; SURFACE WATERS; H2O2; SEAWATER; SEA; VARIABILITY; RAINWATER; OXIDATION; SUNLIGHT; MEXICO AB The near-surface distribution and processes controlling the distribution of hydrogen peroxide were examined in the South and central Atlantic Ocean during a transect from Uruguay to Barbados in May and June 1996. Four kinds of held experiments were conducted during the cruise including diel observations, dark decay experiments, photochemical production experiments, and hydrogen peroxide-enrichment experiments. Significant diel variations (similar to 25 nM) of hydrogen peroxide were observed, with surface-water concentrations increasing during the day and decreasing at night. With a dark decay half-life of 5.5 days and a net rate of photochemical production of 8.3 nM/h at local noon, it appears that both decay rate and photo-production rate of hydrogen peroxide are much smaller in oligotrophic seawater than in coastal seawater. The experimental results indicate that: (1) the decay reaction is a second-order reaction over all, first-order with both the concentration of hydrogen peroxide and the concentration of colloidal material; (2) seawater in the study area could restore its ambient levels of hydrogen peroxide in about 4d after external perturbations. A total of 20 vertical profiles were obtained at 11 stations that can be classified as: surface maximum, surface mixed, and sub-surface maximum. Generally, the concentration of H2O2 decreased with depth to less than 5 nM below 200 m. Hydrogen peroxide also was determined in some water samples from below 200 m, which revealed a slight increase of hydrogen peroxide with depth. In the surface waters of the open ocean, hydrogen peroxide increased with latitude from about 24 nM in the south (33.8 degreesS) to about 80 nM in the north (8.9 degreesN). This latitudinal variation of hydrogen peroxide correlated with model-calculated solar irradiance, satellite-measured wet deposition, depth of the mixed layer, and possibly total organic carbon. The water-column hydrogen peroxide inventory varied from 1.5 to 6.3 x 10(-3) mol/m(2). Although the greatest shallow water concentrations were observed at stations in the Amazon plume, these stations showed a dramatic decrease in hydrogen peroxide with depth and integrated-water-column hydrogen peroxide was not significantly higher than at open ocean stations. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 Univ So Mississippi, Dept Marine Sci, Stennis Space Ctr, MS 39529 USA. RP Yuan, JC (reprint author), NASA, Earth Syst Sci Off, Stennis Space Ctr, MS 39529 USA. OI Shiller, Alan/0000-0002-2068-7909 NR 40 TC 58 Z9 59 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0645 J9 DEEP-SEA RES PT II JI Deep-Sea Res. Part II-Top. Stud. Oceanogr. PY 2001 VL 48 IS 13 BP 2947 EP 2970 DI 10.1016/S0967-0645(01)00026-1 PG 24 WC Oceanography SC Oceanography GA 445XL UT WOS:000169483800011 ER PT S AU Clark, N AF Clark, N BE Chiao, JC TI Intelligent star tracker SO DEVICE AND PROCESS TECHNOLOGIES FOR MEMS AND MICROELECTRONICS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Device and Process Technologies for MEMS and Microelectronics II CY DEC 17-19, 2001 CL ADELAIDE, AUSTRALIA SP SPIE, USAF, Off Sci Res, Asian Off Aerosp Res & Dev, Adelaide Univ, Ctr Biomed Engn, DSTO, Dept Ind & Trade S Australia AB Current state-of-the-art commercial star sensors typically weigh 15 pounds, attain 5 to 10 arc-second accuracy, and use roughly 10 watts of power. Unfortunately, the current state-of-the-art commercial star sensors do not meet many of NASA's "next-generation" spacecraft and instrument needs. Nor do they satisfy Air Force's needs for micro/nanosatellite systems. In an effort to satisfy micro/nano satellite mission needs the Air Force Research Laboratory is developing an intelligent star Tracker, called IntelliStar, which incorporates several novel technologies including Silicon carbide optical housing, MEMs based adaptive optic technologies, smart active pixels, and algebraic coding theory. The design considerations associated with the development of the IntelliStar system are presented along with experimental results which characterize each technologies contribution to overall system performance. In addition to being light weight, the IntelliStar System offers advantages in speed, size, power consumption, and radiation tolerance. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Clark, N (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 10 TC 2 Z9 2 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4322-0 J9 P SOC PHOTO-OPT INS PY 2001 VL 4592 BP 216 EP 226 DI 10.1117/12.448968 PG 11 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Optics SC Engineering; Instruments & Instrumentation; Optics GA BU07E UT WOS:000174910000023 ER PT B AU Fleck, B AF Fleck, B BE Hanslmeier, A Messerotti, M Veronig, A TI Highlights from SOHO and future space missions SO DYNAMIC SUN, PROCEEDINGS SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT Summer School and Workshop on the Dynamic Sun CY AUG 30-SEP 10, 1999 CL SOLAR OBSERV KANZELHOHE, KARNTEN, AUSTRIA HO SOLAR OBSERV KANZELHOHE DE Sun; solar interior; solar corona; solar wind; SOHO ID MICHELSON DOPPLER IMAGER; DIAGNOSTIC SPECTROMETER CDS; MODE FREQUENCY SPLITTINGS; LOCAL INTERSTELLAR-MEDIUM; REGION EXPLOSIVE EVENTS; POLAR CORONAL HOLES; SPEED SOLAR-WIND; TRANSITION-REGION; QUIET-SUN; ACTIVE-REGION AB The Solar and Heliospheric Observatory (SOHO) has provided an unparalleled breadth and depth of information about the Sun, from its interior, through the hot and dynamic atmosphere, out to the solar wind. Analysis of the helioseismology data from SOHO has shed new light on a number of structural and dynamic phenomena in the solar interior, such as the absence of differential rotation in the radiative zone, subsurface zonal and meridional flows, sub-convection-zone mixing, a possible circumpolar jet, and very slow polar rotation. Evidence for an upward transfer of magnetic energy from the Sun's surface toward the corona has been established. The ultraviolet instruments have revealed an extremely dynamic solar atmosphere where plasma flows play an important role. Electrons in coronal holes were found to be relatively "cool", whereas heavy ions are extremely hot and have highly anisotropic velocity distributions. The source regions for the high speed solar wind has been identified and the acceleration profiles of both the slow and fast solar wind have been measured. This paper tries to summarize some of the most recent findings from the SOHO mission. Present plans for future solar space missions are also briefly discussed. C1 NASA, Goddard Space Flight Ctr, ESA Space Sci Dept, Greenbelt, MD 20771 USA. RP Fleck, B (reprint author), NASA, Goddard Space Flight Ctr, ESA Space Sci Dept, Mailcode 682-3, Greenbelt, MD 20771 USA. RI Fleck, Bernhard/C-9520-2012 NR 133 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-6915-7 J9 ASTROPHYS SPACE SC L PY 2001 VL 259 BP 1 EP 41 PG 41 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS47J UT WOS:000169962800001 ER PT B AU Ruzmaikin, A AF Ruzmaikin, A BE Chossat, P Ambruster, D Oprea, I TI The solar dynamo: Axial symmetry and homegeneity broken SO DYNAMO AND DYNAMICS, A MATHEMATICAL CHALLENGE SE NATO SCIENCE SERIES, SERIES II: MATHEMATICS, PHYSICS AND CHEMISTRY LA English DT Proceedings Paper CT NATO Advanced Research Workshop on Dynamo and Dynamics, a Mathematical Challenge CY AUG 21-26, 2000 CL CARGESE, FRANCE SP NATO, CNRS, Natl Sci Fdn ID ACTIVE REGIONS; MAGNETIC-FIELD; CONVECTION; PATTERNS; ROTATION C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ruzmaikin, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 25 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-7069-4 J9 NATO SCI SER II MATH PY 2001 VL 26 BP 289 EP 296 PG 8 WC Astronomy & Astrophysics; Physics, Mathematical SC Astronomy & Astrophysics; Physics GA BU28A UT WOS:000175559200034 ER PT J AU Owen, T Niemann, H Mahaffy, P AF Owen, T Niemann, H Mahaffy, P TI Nitrogen on the Moon: What does it tell us? SO EARTH MOON AND PLANETS LA English DT Article ID LUNAR REGOLITH; SOLAR; JUPITER; ORIGIN; RATIOS; SPECTROMETER; ATMOSPHERES; ABUNDANCES; ISOTOPES; N-15 AB The lunar regolith contains gases that have been implanted in its grains by the solar wind. These gases include nitrogen, and measurements of N-15/N-14 in lunar soils have revealed puzzling temporal variations. These variations have frustrated attempts to determine the value of N-15/N-14 in proto-solar nitrogen. A new measurement of this important isotope ratio on Jupiter allows us to clarify the lunar problems and to establish relationships among nitrogen reservoirs in the solar system and the galaxy. C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Owen, T (reprint author), Univ Hawaii, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. RI Mahaffy, Paul/E-4609-2012 NR 32 TC 2 Z9 2 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 2001 VL 85-6 BP 343 EP 350 PG 8 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 472PQ UT WOS:000170993100028 ER PT J AU Hesse, M Schindler, K AF Hesse, M Schindler, K TI The onset of magnetic reconnection in the magnetotail SO EARTH PLANETS AND SPACE LA English DT Article; Proceedings Paper CT Symposium on Magnetic Reconnection in Space and Laboratory Plasmas CY FEB 29-MAR 04, 2000 CL UNIV TOKYO, TOKYO, JAPAN HO UNIV TOKYO ID 2-DIMENSIONAL CURRENT SHEETS; PARTICLE SIMULATION; COLLISIONLESS RECONNECTION; ELECTRON DISSIPATION; EARTHS MAGNETOPAUSE; HYBRID SIMULATIONS; PLASMA; FIELD; INSTABILITY; DYNAMICS AB This paper addresses the onset of collisionless magnetic reconnection in the tail of the Earth's magnetosphere. The two-and-a-half-dimensional version of a fully electromagnetic particle-in-cell code is used to describe the pre- and post-onset dynamics of reconnection in thin current sheets in the magnetotail. The ion/electron mass ratio is set to 100. The simulation starts out from an apparently stable equilibrium configuration. Applying an external electric field, meant to be caused by magnetic flux transfer to the tail, leads to the formation of a thin current sheet in the center of the plasma sheet. This confirms earlier results obtains with fluid and hybrid-methods. In the thin sheet quasi-static force-balance leads to a substantial decrease of the north-south component of the magnetic field in the center of the sheet. This in turn causes the electrons to become significantly nongyrotropic, such that a tearing mode starts growing, Regarding the nonideal process that supports the electric field in the diffusion region, the simulation results are shown to be consistent with the notion that electron pressure anisotropies associated with the nongyrotropy generate the required diffusive electric fields. The destabilizing role of electron nongyrotropy is confirmed by a simplified analysis of the energy principle for two-dimensional collisionless plasmas. C1 NASA, Goddard Space Flight Ctr, Electrodynam Branch, Greenbelt, MD 20771 USA. Ruhr Univ Bochum, D-4630 Bochum, Germany. RP Hesse, M (reprint author), NASA, Goddard Space Flight Ctr, Electrodynam Branch, Greenbelt, MD 20771 USA. EM michael.hesse@gsfc.nasa.gov RI Hesse, Michael/D-2031-2012 NR 43 TC 26 Z9 26 U1 0 U2 1 PU SPRINGER HEIDELBERG PI HEIDELBERG PA TIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANY SN 1880-5981 J9 EARTH PLANETS SPACE JI Earth Planets Space PY 2001 VL 53 IS 6 BP 645 EP 653 PG 9 WC Geosciences, Multidisciplinary SC Geology GA 459FB UT WOS:000170239400036 ER PT J AU Verigin, M Kotova, G Szabo, A Slavin, J Gombosi, T Kabin, K Shugaev, F Kalinchenko, A AF Verigin, M Kotova, G Szabo, A Slavin, J Gombosi, T Kabin, K Shugaev, F Kalinchenko, A TI Wind observations of the terrestrial bow shock: 3-D shape and motion SO EARTH PLANETS AND SPACE LA English DT Article ID SOLAR-WIND; MACH NUMBERS; MAGNETOPAUSE; SIMULATIONS; ORIENTATION; DIMENSIONS; POSITION; LOCATION AB Between late 1994 and early 2001 the Wind orbiter, generally targeted to stay in the solar wind, passed through the Earth's magnetosphere similar to 50 times. About 450 distinct bow shock crossings were collected during the inbound and outbound bracketing each Wind perigee. These crossings and corresponding vectorial upstream solar wind measurements by the Wind MFI and SWE instruments are used to study the 3-D shape of the bow shock and its motion. Mapping of bow shock crossings to the Sun-Earth line and to the terminator plane is realized using a recent analytical model of the planetary bow shock. The asymmetry of the terrestrial bow shock in the terminator plane is studied as a function of Friedrichs diagram anisotropy. Analysis of the subsolar bow shock position as a function of Alfvenic Mach number M-a during intervals of magnetic field aligned solar wind flow shows that the shock tends to approach the Earth when M-a is decreasing, while for non field-aligned flows bow shock moves from the planet. C1 Russian Acad Sci, Space Res Inst, Moscow 117810, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Univ Alberta, Edmonton, AB T6G 2J1, Canada. Moscow MV Lomonosov State Univ, Fac Phys, Moscow 119899, Russia. RP Verigin, M (reprint author), Russian Acad Sci, Space Res Inst, Profsoyuznaya 84-32, Moscow 117810, Russia. RI Slavin, James/H-3170-2012; Gombosi, Tamas/G-4238-2011 OI Slavin, James/0000-0002-9206-724X; Gombosi, Tamas/0000-0001-9360-4951 NR 26 TC 25 Z9 26 U1 1 U2 4 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO, 158, JAPAN SN 1343-8832 J9 EARTH PLANETS SPACE JI Earth Planets Space PY 2001 VL 53 IS 10 BP 1001 EP 1009 PG 9 WC Geosciences, Multidisciplinary SC Geology GA 488BN UT WOS:000171914700007 ER PT J AU Hiroi, T Pieters, CM Vilas, F Sasaki, S Hamabe, Y Kurahashi, E AF Hiroi, T Pieters, CM Vilas, F Sasaki, S Hamabe, Y Kurahashi, E TI The mystery of 506.5 nm feature of reflectance spectra of Vesta and Vestoids: Evidence for space weathering? SO EARTH PLANETS AND SPACE LA English DT Article; Proceedings Paper CT Western Pacific Geophysics Meeting (WPGM) CY JUN 27-30, 2000 CL TOKYO, JAPAN ID SURFACE; METEORITES; PYROXENE; SAMPLES AB Although asteroid 4 Vesta and Vestoids have been believed to be the source of a group of basaltic meteorites called HEDs, there have been detailed spectral analyses on the spectral redness and the 506.5 nm absorption band, suggesting controversy on their space weathering processes and origins. In order to evaluate a possibility that such an apparent inconsistency may be explained by the space weathering, the 506.5 nm spectral feature and reddening trend are examined for Vesta and Vestoids, HED meteorites, lunar soils, and laser irradiated pyroxene samples in this paper. Our results indicate that all fresh HED meteorites have the 506.5 nm band at different wavelengths according to their classes, lunar soils seem to lose the 506.5 nm band as they mature, and pulse laser irradiation on the pyroxene sample seems to reduce the 506.5 nm band. Therefore, absence of the 506.5 nm band on some Vestoids can be due to space weathering although the relationship between the visible redness and presence/absence of the 506.5 nm band of Vesta and Vestoids is inconsistent with the assumed HED-lunar space weathering trend based on the above laboratory results. Other possible explanations are that some Vestoids experienced shock heavy enough to erase the 506.5 nm band and that pyroxenes on some Vestoids are not similar to those in HED meteorites. Even if the latter case is true and some Vestoids are not made of HED materials, HED meteorites could still come from Vesta unless we assume all Vestoids have to be fragments of Vesta. C1 Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. NASA, Johnson Space Ctr, SN3, Houston, TX 77058 USA. Univ Tokyo, Dept Earth & Planetary Sci, Tokyo 1130033, Japan. RP Hiroi, T (reprint author), Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. NR 16 TC 17 Z9 17 U1 0 U2 2 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO, 158, JAPAN SN 1343-8832 J9 EARTH PLANETS SPACE JI Earth Planets Space PY 2001 VL 53 IS 11 BP 1071 EP 1075 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 498QD UT WOS:000172521400006 ER PT J AU Sykes, MV Vilas, F AF Sykes, MV Vilas, F TI Closing in on HED meteorite sources SO EARTH PLANETS AND SPACE LA English DT Article; Proceedings Paper CT Western Pacific Geophysics Meeting (WPGM) CY JUN 27-30, 2000 CL TOKYO, JAPAN ID ASTEROID FAMILIES; PARENT BODY; VESTA; EVOLUTION; ORIGIN; SIZE AB Members of the Vesta dynamical family have orbital elements consistent with ejecta from a single large excavating collision from a single hemisphere of Vesta. The portion of Vesta's orbit at which such an event must have occurred is slightly constrained and depends on the hemisphere impacted. There is some evidence for subsequent disruptions of these ejected objects. Spectroscopy suggests that the dynamical family members are associated with material from Vesta's interior that was excavated by the event giving rise to the crater covering much of Vesta's southern hemisphere. The 505-nm pyroxene feature seen in RED meteorites is relatively absent in a sample of Vesta dynamical family members raising the question of whether this collisional event was the source of the HED meteorites. Asteroids spectroscopically associated with Vesta that possess this feature are dynamically distinct and could have arisen from a different collisional event on Vesta or originated from a body geochemically similar to Vesta that was disrupted early in the history of the solar system. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. NASA, Lyndon B Johnson Space Ctr, SN3, Houston, TX 77058 USA. RP Sykes, MV (reprint author), Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. NR 29 TC 8 Z9 8 U1 0 U2 1 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO, 158, JAPAN SN 1343-8832 J9 EARTH PLANETS SPACE JI Earth Planets Space PY 2001 VL 53 IS 11 BP 1077 EP 1083 PG 7 WC Geosciences, Multidisciplinary SC Geology GA 498QD UT WOS:000172521400007 ER PT J AU Margasahayam, R Halsey, T AF Margasahayam, R Halsey, T TI Structural impact of rocket motor sound and vibration SO EE-EVALUATION ENGINEERING LA English DT Article AB Sometimes, testing in a lab is just impossible. Find out how data is collected at a site very unfriendly to both man and machine-the launch pad of a space shuttle. C1 NASA, John F Kennedy Space Ctr, DYNACS Engn, Washington, DC 20546 USA. Sony Precis Technol Amer, Lake Forest, CA 92630 USA. RP Margasahayam, R (reprint author), NASA, John F Kennedy Space Ctr, DYNACS Engn, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU NELSON PUBLISHING PI NOKOMIS PA 2504 NORTH TAMIAMI TRAIL, NOKOMIS, FL 34275-3482 USA SN 0149-0370 J9 EE-EVAL ENG JI EE-Eval. Eng. PD JAN PY 2001 VL 40 IS 1 BP 52 EP + PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 392PZ UT WOS:000166421400006 ER PT B AU Khatib, L Muscettola, N Havelund, K AF Khatib, L Muscettola, N Havelund, K GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Mapping temporal planning constraints into timed automata SO EIGHTH INTERNATIONAL SYMPOSIUM ON TEMPORAL REPRESENTATION AND REASONING, PROCEEDINGS LA English DT Proceedings Paper CT 8th International Symposium on Temporal Representation and Reasoning (TIME 2001) CY JUN 14-16, 2001 CL CIVIDALE DEL FRIULI, ITALY SP Univ Milan, Dipartmento Sci Informaz, Univ Udine, Italian Assoc Artificial Intelligence DE time in AI; temporal representation and constraints; timed automata; planning; scheduling; model checking; validation AB Planning and Model Checking are similar in concept. They both deal with reaching a goal state from an initial state by applying specified rules that allow for the transition from one state to another Exploring the relationship between them is an interesting new research area. We are interested in planning frameworks that combine both planning and scheduling. For that, we focus our attention on real time model checking. As a first step, we developed a mapping from planning domain models into timed automata. Since timed automata are the representation structure of real-time model checkers, we are able to exploit what model checking has to offer for planning domains. In this paper we present the mapping algorithm, which involves translating temporal specifications into timed automata, and list some of the planning domain questions someone can answer by rising model checking. C1 NASA, Ames Res Ctr, Kestrel Technol, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Kestrel Technol, Moffett Field, CA 94035 USA. EM lina@ptolemy.arc.nasa.gov; mus@ptolemy.arc.nasa.gov; havelund@ptolemy.arc.nasa.gov NR 14 TC 1 Z9 2 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1107-4 PY 2001 BP 21 EP 27 DI 10.1109/TIME.2001.930693 PG 7 WC Computer Science, Artificial Intelligence SC Computer Science GA BT13X UT WOS:000172045900004 ER PT S AU Pike, WT Hecht, MH Smith, PH Staufer, U AF Pike, WT Hecht, MH Smith, PH Staufer, U BE Aindow, M Kiely, CJ TI A microscopy station for Mars SO ELECTRON MICROSCOPY AND ANALYSIS 2001 SE INSTITUTE OF PHYSICS CONFERENCE SERIES LA English DT Article; Proceedings Paper CT Conference of the Electron-Microscopy-and Analysis-Group CY SEP 05-07, 2001 CL UNIV DUNDEE, DUNDEE, SCOTLAND SP Electron Microscopy & Anal Grp, Royal Microscop Soc, Inst Mat HO UNIV DUNDEE AB We have developed, built and tested a microscopy station for planetary science applications, in particular for the study of Martian dust and soil. The system consists of a sample delivery system, an optical microscope and an atomic force microscope (AFM). The combination of microscopies allows the study of features from the millimeter to nanometer scale. LED illumination allows for full colour and UV optical imaging of the samples. The AFM uses an array of silicon and molded diamond tips and can operate in both, static and dynamic mode. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Lunar & Planetary Lab, Dept Planetary Sci, Tucson, AZ 85721 USA. Univ Neuchatel, Inst Microtechnol, CH-2007 Neuchatel, Switzerland. Univ London Imperial Coll Sci Technol & Med, Dept Elect & Elect Engn, London SW7 2BT, England. RP Pike, WT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Staufer, Urs/J-6866-2016 OI Staufer, Urs/0000-0002-3519-6467 NR 3 TC 1 Z9 1 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0951-3248 BN 0-7503-0812-5 J9 INST PHYS CONF SER PY 2001 IS 168 BP 163 EP 166 PG 4 WC Instruments & Instrumentation; Materials Science, Characterization & Testing; Microscopy; Physics, Multidisciplinary SC Instruments & Instrumentation; Materials Science; Microscopy; Physics GA BU50T UT WOS:000176200500039 ER PT S AU Anderson, MS Pike, WT AF Anderson, MS Pike, WT BE Aindow, M Kiely, CJ TI Chemical imaging with a Raman atomic-force microscope SO ELECTRON MICROSCOPY AND ANALYSIS 2001 SE INSTITUTE OF PHYSICS CONFERENCE SERIES LA English DT Article; Proceedings Paper CT Conference of the Electron-Microscopy-and Analysis-Group CY SEP 05-07, 2001 CL UNIV DUNDEE, DUNDEE, SCOTLAND SP Electron Microscopy & Anal Grp, Royal Microscop Soc, Inst Mat HO UNIV DUNDEE ID OPTICAL MICROSCOPE; SINGLE MOLECULES; SCATTERING; SPECTROSCOPY; TIP AB By integrating an atomic force microscope incorporating a metallized tip with a Raman spectrometer, it is possible to extract chemical information via optical spectroscopy well below the conventional diffraction limit of the incident radiation. The Raman atomic-force microscope utilizes the surface-enhanced Raman signal due to the tip-sample interaction to localize the spectral information. Metallic nanoparticles on the tip provide massive field enhancements to amplify the usually weak Raman signal. The resulting highly localized signal provides chemical information via the Raman spectrum at an unprecedented scale. Side illumination allows for the analysis of opaque samples. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ London Imperial Coll Sci Technol & Med, Dept Elect & Elect Engn, London SW7 2BT, England. RP Anderson, MS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0951-3248 BN 0-7503-0812-5 J9 INST PHYS CONF SER PY 2001 IS 168 BP 501 EP 504 PG 4 WC Instruments & Instrumentation; Materials Science, Characterization & Testing; Microscopy; Physics, Multidisciplinary SC Instruments & Instrumentation; Materials Science; Microscopy; Physics GA BU50T UT WOS:000176200500123 ER PT J AU Lorenz, RD Lunine, JI McKay, CP AF Lorenz, RD Lunine, JI McKay, CP TI Geologic settings for aqueous organic synthesis on Titan revisited SO ENANTIOMER LA English DT Article ID ATMOSPHERE; HISTORY; PHOTOCHEMISTRY; SURFACE; ENERGY; ORIGIN; SYSTEM; MODEL; OCEAN; LIFE AB The photochemistry in Titan's cold reducing atmosphere is an evolutionary dead end. However, the hydrocarbons and nitriles deposited from the atmosphere can undergo aqueous synthesis into prebiotic molecules in ephemeral settings such as impact melt sheets. We re-examine the longevity of aqueous solutions on Titan, noting that recent measurements of the thermal conductivity of ammonia-rich ices suggest that the melt pockets may be longer-lived than previously thought. We propose an important role in surface organic reactions for ultraviolet sunlight transported to the surface as chemical energy stored in acetylene and released by polymerization at Titan's surface. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA USA. RP Lorenz, RD (reprint author), Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RI Lorenz, Ralph/B-8759-2016 OI Lorenz, Ralph/0000-0001-8528-4644 NR 45 TC 14 Z9 14 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 1024-2430 J9 ENANTIOMER JI Enantiomer PY 2001 VL 6 IS 2-3 BP 83 EP 96 PG 14 WC Biochemistry & Molecular Biology; Chemistry, Multidisciplinary; Chemistry, Organic SC Biochemistry & Molecular Biology; Chemistry GA 472BB UT WOS:000170962200003 PM 11570428 ER PT J AU Ryan, MA Lewis, NS AF Ryan, MA Lewis, NS TI Low power, lightweight vapor sensing using arrays of conducting polymer composite chemically-sensitive resistors SO ENANTIOMER LA English DT Article DE vapor detectors; electronic nose; conducting polymer composites ID ELECTRONIC NOSE; DETECTORS AB Arrays of broadly responsive vapor detectors can be used to detect, identify, and quantify vapors and vapor mixtures. One implementation of this strategy involves the use of arrays of chemically-sensitive resistors made from conducting polymer composites. Sorption of an analyte into the polymer composite detector leads to swelling of the film material. The swelling is in turn transduced into a change in electrical resistance because the detector films consist of polymers filled with conducting particles such as carbon black. The differential sorption, and thus differential swelling, of an analyte into each polymer composite in the array produces a unique pattern for each different analyte of interest. Pattern recognition algorithms are then used to analyze the multivariate data arising from the responses of such a detector array. Chiral detector films can provide differential detection of the presence of certain chiral organic vapor analytes. Aspects of the spaceflight qualification and deployment of such a detector array, along with its performance for certain analytes of interest in manned life support applications, are reviewed and summarized in this article. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. CALTECH, Arthur Amos Noyes Lab Chem Phys, Div Chem & Chem Engn, Pasadena, CA 91125 USA. RP Ryan, MA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 18 TC 15 Z9 15 U1 0 U2 5 PU GORDON BREACH PUBLISHING, TAYLOR & FRANCIS GROUP PI PHILADELPHIA PA 325 CHESTNUT ST, 8TH FL, PHILADELPHIA, PA 19106 USA SN 1024-2430 J9 ENANTIOMER JI Enantiomer PY 2001 VL 6 IS 2-3 BP 159 EP 170 PG 12 WC Biochemistry & Molecular Biology; Chemistry, Multidisciplinary; Chemistry, Organic SC Biochemistry & Molecular Biology; Chemistry GA 472BB UT WOS:000170962200010 PM 11570422 ER PT S AU Morris, RD Smelyanskiy, VN Cheeseman, PC AF Morris, RD Smelyanskiy, VN Cheeseman, PC BE Figueiredo, MAT Zerubia, J Jain, AK TI Matching images to models - Camera calibration for 3-D surface reconstruction SO ENERGY MINIMIZATION METHODS IN COMPUTER VISION AND PATTERN RECOGNITION SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Workshop on Energy Minimization Methods in Computer Vision and Pattern Recognition CY SEP 03-05, 2001 CL SOPHIA ANTIPOLIS, FRANCE SP INRIA, Int Assoc Pattern Recognit, Conseil Gen Alpes Maritimes ID ALGORITHM AB In a previous paper we described a system which recursively recovers a-super-resolved three dimensional surface model from a set of images of the surface. In that paper we assumed that the camera calibration for each image was known. In this paper we solve two problems. Firstly, if an estimate of the surface is already known, the problem is to calibrate a new image relative to the existing surface model. Secondly, if no surface estimate is available, the relative camera calibration between the images in the set must be estimated. This will allow an initial surface model to be estimated. Results of both types of estimation are given. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Morris, RD (reprint author), NASA, Ames Res Ctr, MS269-2, Moffett Field, CA 94035 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-42523-3 J9 LECT NOTES COMPUT SC PY 2001 VL 2134 BP 105 EP 117 PG 13 WC Computer Science, Artificial Intelligence; Computer Science, Theory & Methods; Mathematics, Applied; Imaging Science & Photographic Technology; Statistics & Probability SC Computer Science; Mathematics; Imaging Science & Photographic Technology GA BV94A UT WOS:000180456900008 ER PT S AU Kubota, T Huntsberger, T Martin, JT AF Kubota, T Huntsberger, T Martin, JT BE Figueiredo, MAT Zerubia, J Jain, AK TI Edge based probabilistic relaxation for sub-pixel contour extraction SO ENERGY MINIMIZATION METHODS IN COMPUTER VISION AND PATTERN RECOGNITION SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Workshop on Energy Minimization Methods in Computer Vision and Pattern Recognition CY SEP 03-05, 2001 CL SOPHIA ANTIPOLIS, FRANCE SP INRIA, Int Assoc Pattern Recognit, Conseil Gen Alpes Maritimes DE feature extraction; relaxation labelling; segmentation ID PRIMARY VISUAL-CORTEX; ANISOTROPIC DIFFUSION; LABELING PROCESSES; INTEGRATION; COMPUTATION; PROJECTION AB The paper describes a robust edge and contour extraction technique under two types of degradation: random noise and aliasing. The technique employs unambiguous probabilistic relaxation to distinguish features from noise and refine their spatial locations at sub-pixel accuracy. The most important component in the probabilistic relaxation is a compatibility function. The paper suggests a function with which the optimal orientation of edges can be derived analytically, thus allowing an efficient implementation of the relaxation process. A contour extraction algorithm is designed by combining the relaxation process and a perceptual organization technique. Results on both synthetic and natural images are given and show effectiveness of our approach against noise and aliasing. C1 Univ S Carolina, Dept Comp Sci & Engn, Columbia, SC 29205 USA. Jet Prop Lab, Pasadena, CA 91109 USA. RP Kubota, T (reprint author), Univ S Carolina, Dept Comp Sci & Engn, Columbia, SC 29205 USA. NR 26 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-42523-3 J9 LECT NOTES COMPUT SC PY 2001 VL 2134 BP 328 EP 343 PG 16 WC Computer Science, Artificial Intelligence; Computer Science, Theory & Methods; Mathematics, Applied; Imaging Science & Photographic Technology; Statistics & Probability SC Computer Science; Mathematics; Imaging Science & Photographic Technology GA BV94A UT WOS:000180456900022 ER PT J AU Noor, AK Wasfy, TM AF Noor, AK Wasfy, TM TI Simulation of physical experiments in immersive virtual environments SO ENGINEERING COMPUTATIONS LA English DT Article DE computational methods; numerical modelling; software; VR ID REALITY; PERFORMANCE; ISSUES AB An object-oriented event-driven immersive virtual environment is described for the creation of virtual labs (VLs) for simulating physical experiments. Discussion focuses opt a number of aspects of the VLs, including interface devices, software objects, and various applications The VLs interface audit output devices, including immersive stereoscopic screen(s) and stereo speakers; and a variety of input devices, including body tracking (head and hands), haptic gloves, wand, joystick, mouse, microphone, and keyboard The VL incorporates the following types of primitive software objects: interface objects, support objects, geometric entities, and finite elements. Each object encapsulates a set of properties, methods, and events that define its behaviour, appearance, and functions. A "container" object allows grouping of several al objects. Applications of the VLs include viewing the results of the physical experiment, viewing a computer simulation of the physical experiment simulation of the experiments procedure, computational steering, and remote control of the physical experiment In addition. the VL can be used as a risk-free (safe) environment for training. The implementation of virtual structures testing machines, virtual wind tunnels, and a virtual acoustic testing facility is described. C1 Old Dominion Univ, Ctr Adv Engn Environm, NASA, Langley Res Ctr, Hampton, VA USA. RP Noor, AK (reprint author), Old Dominion Univ, Ctr Adv Engn Environm, NASA, Langley Res Ctr, Hampton, VA USA. NR 29 TC 9 Z9 10 U1 0 U2 4 PU MCB U P LIMITED PI BRADFORD PA 60/62 TOLLER LANE, BRADFORD BD8 9BY, W YORKSHIRE, ENGLAND SN 0264-4401 J9 ENG COMPUTATION JI Eng. Comput. PY 2001 VL 18 IS 3-4 BP 515 EP 538 DI 10.1108/02644400110695062 PG 24 WC Computer Science, Interdisciplinary Applications; Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Computer Science; Engineering; Mathematics; Mechanics GA 445XW UT WOS:000169484700009 ER PT J AU Spievak, LE Wawrzynek, PA Ingraffea, AR Lewicki, DG AF Spievak, LE Wawrzynek, PA Ingraffea, AR Lewicki, DG TI Simulating fatigue crack growth in spiral bevel gears SO ENGINEERING FRACTURE MECHANICS LA English DT Article DE boundary element analysis; fatigue crack growth; crack closure; non-proportional load; gears ID RIM THICKNESS; TOOTH ROOT; PROPAGATION; CONTACT AB The boundary element method and linear elastic fracture mechanics theories ale: used to predict three dimensional fatigue crack trajectories in a spiral bevel pinion under a moving load. It is found that the moving load produces a nonproportional load history in a gear's tooth root. An approach that accounts for fatigue crack closure effects is developed to propagate the crack front under the non-proportional load. The predictions ale compared to experimental results. The sensitivity of the predictions to variations in loading conditions and crack growth rate model parameters is explored. Critical areas that must be understood in greater detail prior to predicting mole accurate crack trajectories and crack growth rates in three dimensions are identified. (C) 2000 Published by Elsevier Science Ltd. C1 Cornell Univ, Cornell Fracture Grp, Ithaca, NY 14853 USA. NASA, USA, Res Lab, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Spievak, LE (reprint author), Cornell Univ, Cornell Fracture Grp, Ithaca, NY 14853 USA. NR 27 TC 29 Z9 31 U1 2 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0013-7944 J9 ENG FRACT MECH JI Eng. Fract. Mech. PD JAN PY 2001 VL 68 IS 1 BP 53 EP 76 DI 10.1016/S0013-7944(00)00089-8 PG 24 WC Mechanics SC Mechanics GA 391CJ UT WOS:000166336300005 ER PT B AU Schneider, WF Utley, DR AF Schneider, WF Utley, DR GP ASEM TI A study of teamwork in a government agency SO ENGINEERING MANAGEMENT: IT'S ABOUT PEOPLE, PROCEEDINGS LA English DT Proceedings Paper CT National Conference of the American-Society-for-Engineering-Management CY OCT 11-13, 2001 CL HUNTSVILLE, AL SP Dept Ind & Syst Engn & Engn Management, Univ Alabama Huntsville AB In today's environment of tight budgets and rapidly changing technology, teamwork is required in an organization to remain efficient and competitive. This study analyzed the eight characteristics of teamwork presented in Teamwork, What Must Go Right, What Can Go Wrong (Larson and LaFasto, 1989) against current and classical literature. A survey was developed to measure the existence of the eight characteristics and was completed by four organizations at a government agency. Management completed a survey to measure performance. The results showed that External Support and Recognition is the common weakness and Principled Leadership was the strongest characteristic. Evidence of correlation was shown between performance and the presence of the teamwork characteristics. Based on the results of the survey, recommendations were provided for improving teamwork in these organizations. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 38 TC 0 Z9 0 U1 0 U2 1 PU AMER SOC ENGINEERING MANAGEMT PI ROLLA PA 310 HARRIS HALL, UMR, ROLLA, MO 65401 USA PY 2001 BP 192 EP 201 PG 10 WC Engineering, Multidisciplinary; Management SC Engineering; Business & Economics GA BY37U UT WOS:000189131500031 ER PT B AU Hamaker, JW AF Hamaker, JW GP ASEM TI Improving space project cost estimating with engineering management variables SO ENGINEERING MANAGEMENT: IT'S ABOUT PEOPLE, PROCEEDINGS LA English DT Proceedings Paper CT National Conference of the American-Society-for-Engineering-Management CY OCT 11-13, 2001 CL HUNTSVILLE, AL SP Dept Ind & Syst Engn & Engn Management, Univ Alabama Huntsville AB Current space project cost models attempt to predict space flight project cost via regression equations, which relate the cost of projects to technical performance metrics (e.g. weight, thrust, power, pointing accuracy etc.). This paper examines the introduction of engineering management parameters to the set of explanatory variables. A number of specific engineering management variables are considered and exploratory regression analysis is performed to determine if there is statistical evidence for cost effects apart from technical aspects of the projects. It is concluded that there are other non-technical effects at work and that further research is warranted to determine if it can be shown that these cost effects are definitely related to engineering management. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC ENGINEERING MANAGEMT PI ROLLA PA 310 HARRIS HALL, UMR, ROLLA, MO 65401 USA PY 2001 BP 251 EP 259 PG 9 WC Engineering, Multidisciplinary; Management SC Engineering; Business & Economics GA BY37U UT WOS:000189131500039 ER PT B AU Prince, FAA AF Prince, FAA GP ASEM TI A failure to communicate: Why management doesn't belive the cost estimate SO ENGINEERING MANAGEMENT: IT'S ABOUT PEOPLE, PROCEEDINGS LA English DT Proceedings Paper CT National Conference of the American-Society-for-Engineering-Management CY OCT 11-13, 2001 CL HUNTSVILLE, AL SP Dept Ind & Syst Engn & Engn Management, Univ Alabama Huntsville AB NASA depends on its engineering cost community to provide cost estimates for new programs and projects, yet management often discounts the value of these cost estimates. This paper examines the reasons for management reluctance to embrace engineering cost estimates from the perspective of professional experience. The focus will be on areas under the control of the cost estimator: model development, estimation of cost, and presentation of results. Specific topics addressed include the role of the cost estimator in program/project formulation, cost model development approaches, and communication between the estimator, other engineering disciplines, and management. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC ENGINEERING MANAGEMT PI ROLLA PA 310 HARRIS HALL, UMR, ROLLA, MO 65401 USA PY 2001 BP 265 EP 270 PG 6 WC Engineering, Multidisciplinary; Management SC Engineering; Business & Economics GA BY37U UT WOS:000189131500041 ER PT B AU Takada, PW Westbrook, JW AF Takada, PW Westbrook, JW GP ASEM TI The impact of organization culture on satisfaction of engineers in technology driven organizations SO ENGINEERING MANAGEMENT: IT'S ABOUT PEOPLE, PROCEEDINGS LA English DT Proceedings Paper CT National Conference of the American-Society-for-Engineering-Management CY OCT 11-13, 2001 CL HUNTSVILLE, AL SP Dept Ind & Syst Engn & Engn Management, Univ Alabama Huntsville ID JOB-SATISFACTION AB In today's technological workplace with the shortage of qualified knowledge workers, the factors that lead to job satisfaction have increasing importance. Past studies have shown that knowledge workers in more organic organizations experience higher job satisfaction levels than their peers in more mechanistic organizations. Knowledge workers in varying organization cultures were surveyed in an effort to determine if there is a relationship between the degree of knowledge worker job satisfaction and the measure of organic organization culture. Two survey instruments, the Organizational Cultural Assessment (OCA) developed by Riegle (1999), and the Minnesota Satisfaction Questionnaire (MSQ) (Weiss, 1977), were utilized. The OCA delineates degree of organic culture present whereas the MSQ measures job satisfaction. Results of both surveys were statistically analyzed to determine if knowledge workers experience higher satisfaction levels in organic organization cultures. A total of eight high technology workplaces were surveyed with five workplaces yielding statistically significant positive correlation between a positive organization culture and increased job satisfaction. These initial results indicate the connection between culture and job satisfaction. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 17 TC 0 Z9 0 U1 1 U2 1 PU AMER SOC ENGINEERING MANAGEMT PI ROLLA PA 310 HARRIS HALL, UMR, ROLLA, MO 65401 USA PY 2001 BP 407 EP 413 PG 7 WC Engineering, Multidisciplinary; Management SC Engineering; Business & Economics GA BY37U UT WOS:000189131500064 ER PT B AU Feary, M Sherry, L Palmer, E Polson, P AF Feary, M Sherry, L Palmer, E Polson, P BE Harris, D TI Formal method for developing training for a modern autopilot SO ENGINEERING PSYCHOLOGY AND COGNITIVE ERGONOMICS VOLUME FIVE: AEROSPACE AND TRANSPORTATION SYSTEMS LA English DT Proceedings Paper CT 3rd International Conference on Engineering Psychology and Cognitive Ergonomics CY OCT 25-27, 2000 CL EDINBURGH, SCOTLAND AB Aircraft automation, particularly the automation surrounding vertical navigation, has been cited as an area of training difficulty and a source of confusion during operation. A number of incidents have been attributed to a lack of crew understanding of what the automation is doing. This paper describes the use of a formal methodology, referred to as the Operational Procedures Method, in the design of interface, procedures and training material for an aircraft vertical guidance system, and an experiments to evaluate a training packages developed from the method. The results of the study showed that this type of training can be successfully delivered via a computer based training device. C1 NASA Ames Res Ctr, Moffett Field, CA 94035 USA. NR 6 TC 0 Z9 0 U1 1 U2 1 PU ASHGATE PUBLISHING LTD PI ALDERSHOT PA GOWER HOUSE, CROFT ROAD, ALDERSHOT GU11 3HR, ENGLAND BN 0-7546-1337-2 PY 2001 BP 233 EP 240 PG 8 WC Ergonomics; Psychology, Applied; Psychology, Experimental; Transportation SC Engineering; Psychology; Transportation GA BU72T UT WOS:000176846500027 ER PT J AU Zheng, Y Weatherill, NP Hassan, O AF Zheng, Y Weatherill, NP Hassan, O TI Topology abstraction of surface models for three-dimensional grid generation SO ENGINEERING WITH COMPUTERS LA English DT Article DE computational simulation; geometry modelling; grid generation; surface model; topology abstraction; user environment AB Surface grid generation and the subsequent volume grid generation is the key to unstructured grid-based computational simulation. The baseline entities of the surface models under consideration for use with the proposed surface grid generator are curves and surfaces. There is a necessity to establish a topology relation between the curves and surfaces, prior to a surface gridding process. The present paper addresses issues related to this topology abstraction. Effort has also been made to generally discuss how to bridge the gap between CAD modelling and surface gridding. The proposed procedures have been incorporated into an Interactive Geometry Utility Environment (IGUE). The IGUE is a sub-environment of a Parallel Simulation User Environment (PSUE), which has been developed for unstructured grid-based computational simulation. Arbitrary computer application software can be integrated into the environment to provide a multi-disciplinary engineering analysis capability within one unified computational framework. Examples of computational applications have been included in the present paper, to demonstrate the use of the PSUE and geometry preparation procedure with an emphasis of topology abstraction. C1 Univ Wales, Dept Civil Engn, Swansea SA2 8PP, W Glam, Wales. RP Zheng, Y (reprint author), NASA, Glenn Res Ctr, MS 5-11,2100 Brookpark Rd, Cleveland, OH 44135 USA. RI Hassan, Oubay/B-1729-2013; Zheng, Yao/A-3913-2016 NR 12 TC 9 Z9 9 U1 0 U2 3 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0177-0667 J9 ENG COMPUT-GERMANY JI Eng. Comput. PY 2001 VL 17 IS 1 BP 28 EP 38 DI 10.1007/s003660170021 PG 11 WC Computer Science, Interdisciplinary Applications; Engineering, Mechanical SC Computer Science; Engineering GA 440RV UT WOS:000169188800003 ER PT S AU Delgado, F Abernathy, MF White, J AF Delgado, F Abernathy, MF White, J BE Verly, JG TI Hybrid synthetic vision system for the X-38 crew return vehicle SO ENHANCED AND SYNTHETIC VISION 2001 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Enhanced and Synthetic Vision 2001 CY APR 16-17, 2001 CL ORLANDO, FL SP SPIE DE synthetic vision; simulation; flight visualization; flight guidance; human factors; and situation awareness AB The X-38 program began in early 1995 and is developing a series of test vehicles to demonstrate the low-cost technologies and methods required to develop a fully functional CRV that can rapidly return astronauts from onboard the International Space Station (ISS) to earth. The X-38 program uses a gradual buildup approach and where appropriate, is taking advantage of advanced technologies that may help improve safety, decrease cost, reduce development time, and outperform traditional technologies. Four atmospheric test vehicles and one space-rated vehicle will be developed and tested during the X-38 program The atmospheric test vehicles are known as vehicle 131 (V131), vehicle 132 (V132), vehicle 131R (V131R), and vehicle 133 (V133). The space-rated vehicle that will fly on the Shuttle in 2002, as a payload bay experiment, is known as vehicle 201 (V201). Since windshields and windows add considerable weight and risk to vehicle design, all the X-38 vehicles employ a windowless cockpit design. This windowless design philosophy and the desire to give crew members and operations personnel as much situational awareness as possible has allowed for the development and demonstration of the benefits of using a synthetic vision system. The system provides a simulated real-time 3D perspective that can be used during all-weather conditions and during day or night operations. The information being displayed on the system is enriched with a wide variety of flight-related information. The system developed has been successfully used during live flight-testing of V132 and V131R. While the advantages of a synthetic vision system are considerable, the major disadvantage of such a system is it's limitation to display a synthetic environment using "static" data that was acquired by an aircraft or satellite, at some point in the past. The next generation synthetic environment system being developed, which we are calling the "3D-HUD", will take advantage of a video camera system to fuse live video imagery with the a computer generated synthetic scene. This hybrid system can display a dynamic, real-time scene of the region of interest, enriched by information from a synthetic environment system. On the X-38 program, this technology will help operators identify any large and significant obstacles that can pose a safety concern during the final flight phase of our test vehicles. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Delgado, F (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 4 TC 0 Z9 0 U1 1 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4058-2 J9 P SOC PHOTO-OPT INS PY 2001 VL 4363 BP 181 EP 188 DI 10.1117/12.438020 PG 8 WC Engineering, Aerospace; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Optics SC Engineering; Computer Science; Optics GA BT20Q UT WOS:000172264500019 ER PT J AU Kyriakidis, PC Dungan, JL AF Kyriakidis, PC Dungan, JL TI A geostatistical approach for mapping thematic classification accuracy and evaluating the impact of inaccurate spatial data on ecological model predictions SO ENVIRONMENTAL AND ECOLOGICAL STATISTICS LA English DT Article; Proceedings Paper CT International Conference of Spatial Statistics for Production Ecology CY APR 19-21, 1999 CL WAGENINGEN, NETHERLANDS DE biogeochemical cycles; classification uncertainty; geographic information systems; indicator kriging; land cover map quality; net primary production; remote sensing; stochastic simulation ID GROUND-BASED RADIOMETRY; SOIL PROPERTIES; KRIGING APPROACH; INFORMATION; SATELLITE; STATISTICS; MAPS AB Spatial information in the form of geographical information system coverages and remotely sensed imagery is increasingly used in ecological modeling. Examples include maps of land cover type from which ecologically relevant properties, such as biomass or leaf area index, are derived. Spatial information, however, is not error-free: acquisition and processing errors, as well as the complexity of the physical processes involved, make remotely sensed data imperfect measurements of ecological attributes. It is therefore important to first assess the accuracy of the spatial information being used and then evaluate the impact of such inaccurate information on ecological model predictions. In this paper, the role of geostatistics for mapping thematic classification accuracy through integration of abundant image-derived (soft) and sparse higher accuracy (hard) class labels is presented. Such assessment leads to local indices of map quality, which can be used for guiding additional ground surveys. Stochastic simulation is proposed for generating multiple alternative realizations (maps) of the spatial distribution of the higher accuracy class labels over the study area. All simulated realizations are consistent with the available pieces of information (hard and soft labels) up to their validated level of accuracy. The simulated alternative class label representations can be used for assessing joint spatial accuracy, i.e., classification accuracy regarding entire spatial features read from the thematic map. Such realizations can also serve as input parameters to spatially explicit ecological models; the resulting distribution of ecological responses provides a model of uncertainty regarding the ecological model prediction. A case study illustrates the generation of alternative land cover maps for a Landsat Thematic Mapper (TM) subscene, and the subsequent construction of local map quality indices. Simulated land cover maps are then input into a biogeochemical model for assessing uncertainty regarding net primary production (NPP). C1 Stanford Univ, Dept Geol & Environm Sci, Palo Alto, CA 94304 USA. Calif State Univ Monteray Bay, NASA, Ames Res Ctr, Moffett Field, CA USA. RP Kyriakidis, PC (reprint author), Stanford Univ, Dept Geol & Environm Sci, Palo Alto, CA 94304 USA. EM pckyriakidis@lbl.gov RI Dungan, Jennifer/G-9921-2016; OI Dungan, Jennifer/0000-0002-4863-1616; Kyriakidis, Phaedon/0000-0003-4222-8567 NR 49 TC 57 Z9 59 U1 3 U2 26 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1352-8505 J9 ENVIRON ECOL STAT JI Environ. Ecol. Stat. PY 2001 VL 8 IS 4 BP 311 EP 330 DI 10.1023/A:1012778302005 PG 20 WC Environmental Sciences; Mathematics, Interdisciplinary Applications; Statistics & Probability SC Environmental Sciences & Ecology; Mathematics GA 491HG UT WOS:000172102500003 ER PT J AU Stein, LY La Duc, MT Grundl, TJ Nealson, KH AF Stein, LY La Duc, MT Grundl, TJ Nealson, KH TI Bacterial and archaeal populations associated with freshwater ferromanganous micronodules and sediments SO ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID RIBOSOMAL-RNA GENES; MANGANESE REDUCTION; SP-NOV; IRON; OXIDATION; EXTRACTION; SEAWATER; OXIDE; LAKE; GB-1 AB Biology is believed to play a large role in the cycling of iron and manganese in many freshwater environments, but specific microbial groups indigenous to these systems have not been well characterized. To investigate the populations of Bacteria and Archaea associated with metal-rich sediments from Green Bay, WI, we extracted nucleic acids and analysed the phylogenetic relationships of cloned 16S rRNA genes. Because nucleic acids have not been routinely extracted from metal-rich samples, we investigated the bias inherent in DNA extraction and gene amplification from pure MnO(2) using defined populations of whole cells or naked DNA, From the sediments, we screened for manganese-oxidizing bacteria using indicator media and found three isolates that were capable of manganese oxidation, In the phylogenetic analysis of bacterial 16S rRNA gene clones, we found two groups related to known metal-oxidizing genera, Leptothrix of the beta -Proteobacteria and Hyphomicrobium of the alpha -Proteobacteria, and a Fe(III)-reducing group related to the Magnetospirillum genus of the alpha -Proteobacteria, Groups related to the metal-reducing delta -Proteobacteria constituted 22% of the gene clones, In addition, gene sequences from one group of methanogens and a group of Crenarchaeota, identified in the archaeal gene clone library, were related to those found previously in Lake Michigan sediments, C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Univ Wisconsin, Dept Geosci, Milwaukee, WI 53201 USA. NASA, Jet Propuls Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. RP Stein, LY (reprint author), CALTECH, Div Geol & Planetary Sci, M-C 170-25,1200 E Calif Ave, Pasadena, CA 91125 USA. EM steinl@gps.caltech.edu RI Stein, Lisa/E-6374-2016 OI Stein, Lisa/0000-0001-5095-5022 NR 42 TC 151 Z9 154 U1 0 U2 50 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1462-2912 J9 ENVIRON MICROBIOL JI Environ. Microbiol. PD JAN PY 2001 VL 3 IS 1 BP 10 EP 18 DI 10.1046/j.1462-2920.2001.00154.x PG 9 WC Microbiology SC Microbiology GA 403RK UT WOS:000167056100002 PM 11225719 ER PT B AU Corcoran, M Ishibashi, K Swank, J Petre, R AF Corcoran, M Ishibashi, K Swank, J Petre, R BE Gull, TR Johansson, S Davidson, K TI Solving the X-ray variability of Eta Carinae SO ETA CARINAE AND OTHER MYSTERIOUS STARS: THE HIDDEN OPPORTUNITIES OF EMISSION LINE SPECTROSCOPY SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Conference on ETA Carinae and Other Mysterious Stars CY AUG 24-26, 2000 CL HVEN, SWEDEN SP Royal Swedish Acad Sci, Crafoord Fdn, Royal Physiog Soc ID LONG-PERIOD BINARY; MILLIMETER EMISSION; MASS-LOSS; ASCA AB We review the X-ray properties of the supermassive LBV eta Carinae, and try to fit the RXTE 2-10 keV X-ray lightcurve with a colliding wind emission model to refine the ground-based orbital elements. Our X-ray lightcurve modelling suggests that the mass loss rate from eta Carinae is generally less than 3 x 10(-4) MD yr(-1), about a factor of 5 lower than that derived from some observations in other wavebands. We could not match the duration of the X-ray minimum with any colliding wind model in which the wind is spherically symmetric and the mass loss rate is constant. However we can improve the model fit around X-ray minimum if we increase the mass loss rate from eta Carinae by a factor of similar to 20 for approximately 80 days following periastron. Based on the X-ray fluxes the distance to eta Carinae is 2300 pc. C1 NASA, Goddard Space Flight Ctr, USRA, LHEA, Greenbelt, MD 20771 USA. RP Corcoran, M (reprint author), NASA, Goddard Space Flight Ctr, USRA, LHEA, Code 662, Greenbelt, MD 20771 USA. RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 24 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-080-3 J9 ASTR SOC P PY 2001 VL 242 BP 41 EP 52 PG 12 WC Astronomy & Astrophysics; Spectroscopy SC Astronomy & Astrophysics; Spectroscopy GA BU31W UT WOS:000175679300004 ER PT B AU Ishibashi, K AF Ishibashi, K BE Gull, TR Johansson, S Davidson, K TI Searching for physically acceptable parameters for Eta Carinae's companion SO ETA CARINAE AND OTHER MYSTERIOUS STARS: THE HIDDEN OPPORTUNITIES OF EMISSION LINE SPECTROSCOPY SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Conference on ETA Carinae and Other Mysterious Stars CY AUG 24-26, 2000 CL HVEN, SWEDEN SP Royal Swedish Acad Sci, Crafoord Fdn, Royal Physiog Soc ID ORBIT C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ishibashi, K (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 5 TC 17 Z9 17 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-080-3 J9 ASTR SOC P PY 2001 VL 242 BP 53 EP 54 PG 2 WC Astronomy & Astrophysics; Spectroscopy SC Astronomy & Astrophysics; Spectroscopy GA BU31W UT WOS:000175679300005 ER PT B AU Iping, R Sonneborn, G Gull, T Massa, D AF Iping, R Sonneborn, G Gull, T Massa, D BE Gull, TR Johansson, S Davidson, K TI The far ultraviolet spectrum of Eta Carinae SO ETA CARINAE AND OTHER MYSTERIOUS STARS: THE HIDDEN OPPORTUNITIES OF EMISSION LINE SPECTROSCOPY SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Conference on ETA Carinae and Other Mysterious Stars CY AUG 24-26, 2000 CL HVEN, SWEDEN SP Royal Swedish Acad Sci, Crafoord Fdn, Royal Physiog Soc AB The first far ultraviolet high spectral resolution observations of eta Carinae were obtained with the Far Ultraviolet Spectroscopic Explorer satellite in February and March 2000. The observed flux at 1150 Angstrom is similar to 4 x 10(-1)2 erg cm(-2) sec(-1) Angstrom(-1). The flux level declines toward the Lyman limit where converging H-2 and Hi features completely blanket the spectrum, The shape of the spectrum shortward of 1110 A is dominated by strong absorption bands of interstellar H-2. In addition to many strong interstellar atomic species, the spectrum contains several prominent P-Cygni features, including C III 1175, S IV 1063-73, Si III 1113, and NI 1134. The lines are broad with unsaturated absorption troughs, implying that the wind is patchy and/or only partly covers the UV emitting surface. The wind absorption extends to similar to -1000 km s(-1). The large far ultraviolet flux levels at 1150-1180 Angstrom, relative to those observed by HST/STIS, imply that the observed far-UV spectrum is formed in an extended (similar to 1 - 2 arcsec diameter) UV scattering envelope. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Iping, R (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 4 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-080-3 J9 ASTR SOC P PY 2001 VL 242 BP 55 EP 58 PG 4 WC Astronomy & Astrophysics; Spectroscopy SC Astronomy & Astrophysics; Spectroscopy GA BU31W UT WOS:000175679300006 ER PT B AU Gull, T Ishibashi, K AF Gull, T Ishibashi, K BE Gull, TR Johansson, S Davidson, K TI The 3-dimensional and time-variant structures of ejecta around Eta Carinae as detected by the STIS SO ETA CARINAE AND OTHER MYSTERIOUS STARS: THE HIDDEN OPPORTUNITIES OF EMISSION LINE SPECTROSCOPY SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Conference on ETA Carinae and Other Mysterious Stars CY AUG 24-26, 2000 CL HVEN, SWEDEN SP Royal Swedish Acad Sci, Crafoord Fdn, Royal Physiog Soc ID NEBULA AB Since New Year's Eve 1998, the Space Telescope Imaging Spectrograph (STIS) has been utilized to characterize the central source and the nebular structures associated with Eta Carinae. In March 1998, long aperture spectra were recorded from 1640 to 10400A with angular resolution of 0.1" and spectral resolving power of about 3000. The aperture position angle was set to include the central source, Weigelt Blobs B and D, an internal emission nebula and the reflection nebulosity of the Homunculus, Approximately 2000 emission lines and numerous absorption lines are detected in the spectra of the Weigelt blobs. Reflected starlight and faint emission line structures extend out to the edge of the Homunculus. We see evidence for shocks at the edge of the Homunculus, a partially ionized structure (the Homunculus), a nebular Balmer absorption structure, bright emission-line nebulosities deeply interior the Homunculus, and an extended atmosphere of the central source. As we repeated the observations in 1999 and 2000, both the central source and the nebulosity brightened. The Weigelt blobs emission line spectra showed evidence for increased excitation and increased ionization. Continued monitoring is intended to follow 97 Car for an entire 5.52 year cycle, and even beyond, as we attempt to separate cyclic changes from longterm changes. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gull, T (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 12 TC 5 Z9 5 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-080-3 J9 ASTR SOC P PY 2001 VL 242 BP 59 EP 70 PG 12 WC Astronomy & Astrophysics; Spectroscopy SC Astronomy & Astrophysics; Spectroscopy GA BU31W UT WOS:000175679300007 ER PT B AU Ishibashi, K Gull, T Davidson, K AF Ishibashi, K Gull, T Davidson, K BE Gull, TR Johansson, S Davidson, K TI The HST/STIS mapping of the Eta Carinae nebulae SO ETA CARINAE AND OTHER MYSTERIOUS STARS: THE HIDDEN OPPORTUNITIES OF EMISSION LINE SPECTROSCOPY SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Conference on ETA Carinae and Other Mysterious Stars CY AUG 24-26, 2000 CL HVEN, SWEDEN SP Royal Swedish Acad Sci, Crafoord Fdn, Royal Physiog Soc AB The bipolar nebula of Eta Carinae is resolved into three structures: the well-known Homunculus nebula, a newly discovered bipolar nebula within the Homunculus, and also newly identified extended nebula absorbing Balmer Hydrogen photons. A spectral mapping of Eta Carinae with the HST/STIS CCD made possible to examine these new features in details. This is a preliminary study of these nebular structures and our immediate goal here is to introduce and describe them with little interpretation on our own. These newly identified structures should be included in any self-consistent plasma or dynamical modeling of the Eta Carinae nebula in the future. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ishibashi, K (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 7 TC 6 Z9 6 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-080-3 J9 ASTR SOC P PY 2001 VL 242 BP 71 EP 80 PG 10 WC Astronomy & Astrophysics; Spectroscopy SC Astronomy & Astrophysics; Spectroscopy GA BU31W UT WOS:000175679300008 ER PT B AU Bautista, M Gull, T Ishibashi, K Hartman, H Davidson, K AF Bautista, M Gull, T Ishibashi, K Hartman, H Davidson, K BE Gull, TR Johansson, S Davidson, K TI Continuum fluorescence excitation of SrII in Eta Carinae SO ETA CARINAE AND OTHER MYSTERIOUS STARS: THE HIDDEN OPPORTUNITIES OF EMISSION LINE SPECTROSCOPY SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Conference on ETA Carinae and Other Mysterious Stars CY AUG 24-26, 2000 CL HVEN, SWEDEN SP Royal Swedish Acad Sci, Crafoord Fdn, Royal Physiog Soc ID GASEOUS NEBULAE; II LINES; NI-II AB We study the nature of the peculiar [Sr II] emission filament found in the ejecta of Eta Carinae. To this purpose we carry out ab initio calculations of radiative transition probabilities and electron impact excitation rate coefficients for Sr H. Then we build a multilevel model for the system which is used to investigate the physical condition of the filament and the nature of the of the observed allowed and forbidden Sr II optical emission. It is found that these lines are pumped by the continuum radiation field in a mostly neutral region with electron density near 10(7)cm(-3). Under these conditions, the observed emission is well explained without the need for a large Sr overabundance. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Bautista, M (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. RI Gull, Theodore/D-2753-2012; Hartman, Henrik/K-3113-2013 OI Gull, Theodore/0000-0002-6851-5380; NR 7 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-080-3 J9 ASTR SOC P PY 2001 VL 242 BP 111 EP 116 PG 6 WC Astronomy & Astrophysics; Spectroscopy SC Astronomy & Astrophysics; Spectroscopy GA BU31W UT WOS:000175679300013 ER PT B AU Gull, T Ishibashi, K Davidson, K Collins, N AF Gull, T Ishibashi, K Davidson, K Collins, N BE Gull, TR Johansson, S Davidson, K TI STIS observations of the eta carinae central source and Weigelt Blobs BD SO ETA CARINAE AND OTHER MYSTERIOUS STARS: THE HIDDEN OPPORTUNITIES OF EMISSION LINE SPECTROSCOPY SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Conference on ETA Carinae and Other Mysterious Stars CY AUG 24-26, 2000 CL HVEN, SWEDEN SP Royal Swedish Acad Sci, Crafoord Fdn, Royal Physiog Soc AB We present extracted spectral plots from 1640 to 10400 A of the central source, 97 Car and Weigelt's Blobs B and D (combined) for three visits with HST and STIS in March 1998, February 1999 and March 2000. The spectra are changing as 77 Car is emerging from the spectroscopic minimum (December 1997 to March 1998) towards a spectroscopic maximum in late 2000. The most dramatic changes were between March 1998 and February 1999. The stellar flux increased and the P Cygni line profiles changed, especially for Balmer alpha. For the Weigelt blobs B and D, the continuum and the singly-ionized elemental species fluxes do not change substantially. Instead, higher excitation and higher ionization emission lines were added to the spectrum. The Weigelt BD blobs spectra will appear in final form with line identifications, currently being prepared by Torgil Zethson as a portion of his dissertation. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gull, T (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 3 TC 21 Z9 21 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-080-3 J9 ASTR SOC P PY 2001 VL 242 BP 391 EP 460 PG 70 WC Astronomy & Astrophysics; Spectroscopy SC Astronomy & Astrophysics; Spectroscopy GA BU31W UT WOS:000175679300051 ER PT S AU Scharton, T AF Scharton, T BE Schurmann, B TI Force limits measured on a space shuttle flight SO EUROPEAN CONFERENCE ON SPACECRAFT STRUCTURES, MATERIALS AND MECHANICAL TESTING, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT European Conference on Spacecraft Structures, Materials and Mechanical Testing CY NOV 29-DEC 01, 2000 CL NOORDWIJK, NETHERLANDS SP CNES, DLR, ESA AB The random vibration forces between a payload and the sidewall of the space shuttle have been measured in flight and compared with the force specifications used in ground vibration tests. The flight data are in agreement with a semiempirical method, which is widely used to predict vibration test force limits. The flight measurements are less than one-half of the random vibration loads specified in the shuttle payload design guide. These data are consistent with published data and have been previously disseminated within NASA and the aerospace community in the USA [1]. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. RP Scharton, T (reprint author), CALTECH, Jet Propuls Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-713-5 J9 ESA SP PUBL PY 2001 VL 468 BP 43 EP 46 PG 4 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Mechanical; Mechanics; Materials Science, Characterization & Testing SC Automation & Control Systems; Engineering; Mechanics; Materials Science GA BS13N UT WOS:000168780000007 ER PT S AU Chang, KY AF Chang, KY BE Schurmann, B TI Force limit specifications vs. design limit loads in vibration testing SO EUROPEAN CONFERENCE ON SPACECRAFT STRUCTURES, MATERIALS AND MECHANICAL TESTING, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT European Conference on Spacecraft Structures, Materials and Mechanical Testing CY NOV 29-DEC 01, 2000 CL NOORDWIJK, NETHERLANDS SP CNES, DLR, ESA AB Flight equipment is exposed to random vibration excitations during launch and is functionally designed to survive a shaker random vibration test. In the test, the random vibration design levels will be applied at the equipment-mounting interface and will be force limited to reduce over-testing at shaker hardmount resonance frequencies. As is commonly practiced for heavier equipment, the equipment also is designed to the structural flight limit load. The philosophy of the limit load factors (LLFs) or so-called the Mass Acceleration Curve (MAC) has been adopted over many years for use in the preliminary structural design of spacecraft and flight equipment. The purpose of the work presented herein is to discuss the results of force limit notching during vibration testing with respect to the traditional limit load design criteria. By using a single-degree-of-freedom (SDOF) system approach, this work shows that with an appropriate force specification the notched response due to force limiting will result in loads comparable with the structural design limit criteria. A simplified formula is presented to predict the test load limits, based only upon estimates for the first significant resonance of the equipment and the semi-empirical force specification factor, C-2. The work is currently being expanded to include two and multi-degree-of-freedom vibratory systems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chang, KY (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 157-410, Pasadena, CA 91109 USA. NR 11 TC 1 Z9 1 U1 1 U2 1 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-713-5 J9 ESA SP PUBL PY 2001 VL 468 BP 295 EP 300 PG 6 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Mechanical; Mechanics; Materials Science, Characterization & Testing SC Automation & Control Systems; Engineering; Mechanics; Materials Science GA BS13N UT WOS:000168780000041 ER PT J AU Fixsen, DJ Cornett, RH AF Fixsen, DJ Cornett, RH TI Implications of the sample rate on large space telescopes SO EXPERIMENTAL ASTRONOMY LA English DT Article DE array detectors; IR detectors; JWST; observation strategies ID COSMIC-RAY REJECTION; ARRAYS AB The frequency at which a large space telescope's (e.g. JWST's) detector chips are read, or the sample rate, is tightly coupled to many hardware and operational aspects of the telescope's instrument and data handling elements. In this paper we discuss many of the drivers and important implications of the sample rate: the data rate to the ground; onboard computer storage, bandwidth, and speed; the number of A-->D chips, and therefore the overall size and power requirements of the analog electronics; cryocabling requirements; and detector noise and power. We discuss and parametrize these and other elements related to sample rate. Finally, we discuss the implications of sample rate in the context of achieving the most important science goals under the constraint of limited cost. C1 NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. RP Fixsen, DJ (reprint author), NASA, Goddard Space Flight Ctr, SSAI, Code 685, Greenbelt, MD 20771 USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0922-6435 J9 EXP ASTRON JI Exp. Astron. PY 2001 VL 12 IS 3 BP 179 EP 193 DI 10.1023/A:1021835102574 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 633EA UT WOS:000180268500003 ER PT J AU DuVarney, R Bleau, C Motter, G Dekany, R Troy, M Brack, G AF DuVarney, R Bleau, C Motter, G Dekany, R Troy, M Brack, G TI SciMeasure wavefront sensor cameras and their application in the Palomar adaptive optics system SO EXPERIMENTAL ASTRONOMY LA English DT Article DE CCD cameras; imaging application AB SciMeasure, in collaboration with Emory University and the Jet Propulsion Laboratory, has developed a very versatile CCD controller for use in adaptive optics, optical interferometry, and other applications requiring high-speed readout rates and/or low read noise. The overall architecture of this controller system will be discussed and its performance using both EEV CCD39 and MIT/LL CCID-19 detectors will be presented. This controller is used in the adaptive optics system, developed by JPL, for the 200'' Hale telescope at Palomar Mountain. Early diffraction-limited science results, recently achieved by the AO system, are presented. We gratefully acknowledge the financial support of NASA through SBIR contracts NAS8-97195 and NAS8-98081. C1 Emory Univ, Dept Phys, Atlanta, GA 30322 USA. INASA, Jet Prop Lab, Pasadena, CA USA. RP DuVarney, R (reprint author), Emory Univ, Dept Phys, Atlanta, GA 30322 USA. NR 11 TC 3 Z9 3 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0922-6435 J9 EXP ASTRON JI Exp. Astron. PY 2001 VL 11 IS 3 BP 237 EP 249 DI 10.1023/A:1013199214825 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 499YM UT WOS:000172598600006 ER PT B AU Echternach, P Williams, CP Dultz, SC Braunstein, S Dowling, JP AF Echternach, P Williams, CP Dultz, SC Braunstein, S Dowling, JP BE Clark, RG TI Universal quantum gates for single cooper pair box based quantum computing SO EXPERIMENTAL IMPLEMENTATION OF QUANTUM COMPUTATION LA English DT Proceedings Paper CT 1st International Conference on Experimental Implementation of Quantum Computation CY JAN 16-19, 2001 CL NATL MARITIME MUSEUM, SYDNEY, AUSTRALIA HO NATL MARITIME MUSEUM ID JOSEPHSON-JUNCTIONS; COMPUTATION; STATES; SUPERPOSITION; QUBITS C1 CALTECH, Jet Prop Lab, Microdevices Lab, Pasadena, CA 91109 USA. RP Echternach, P (reprint author), CALTECH, Jet Prop Lab, Microdevices Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Braunstein, Samuel/A-5501-2009 NR 20 TC 1 Z9 1 U1 0 U2 0 PU RINTON PRESS, INC PI PRINCETON PA 565 EDMUND TERRACE, PRINCETON, NJ 07652 USA BN 1-58949-013-4 PY 2001 BP 111 EP 120 PG 10 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Instruments & Instrumentation; Optics; Physics, Condensed Matter SC Computer Science; Instruments & Instrumentation; Optics; Physics GA BW76D UT WOS:000183080000016 ER PT S AU Macedo, J Manduchi, R Matthies, L AF Macedo, J Manduchi, R Matthies, L BE Rus, D Singh, S TI Ladar-based discrimination of grass from obstacles for autonomous navigation SO EXPERIMENTAL ROBOTICS VII SE LECTURE NOTES IN CONTROL AND INFORMATION SCIENCES LA English DT Article; Proceedings Paper CT 7th International Symposium on Experimental Robotics CY DEC 11-13, 2000 CL WAIKIKI, HAWAII SP Dartmouth Coll, Carnegie Mellon Univ AB Autonomous navigation in vegetated terrain requires the ability to discriminate obstacles from grass, a non-trivial problem when the sensorial world of the robot is based only on range information as provided, for example, by a laser rangefinder (ladar). We present a statistical analysis of the range data produced by a single-axis ladar in different situations, including the case of an obstacle partially occluded by grass. Such analysis inspired a simple classification algorithm, which has been tested on real range data acquired by JPL's urban robot. C1 Univ San Diego, San Diego, CA 92110 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Macedo, J (reprint author), Univ San Diego, San Diego, CA 92110 USA. NR 8 TC 4 Z9 4 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0170-8643 BN 3-540-42104-1 J9 LECT NOTES CONTR INF PY 2001 VL 271 BP 111 EP 120 PG 10 WC Automation & Control Systems; Computer Science, Information Systems; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BU28G UT WOS:000175560500012 ER PT S AU Sturner, SJ AF Sturner, SJ BE Battrick, B TI A model for the distribution of the galactic 1809 keV emission SO EXPLORING THE GAMMA-RAY UNIVERSE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 4th Integral Workshop on Exploring the Gamma-Ray Universe CY SEP 04-08, 2000 CL ALICANTE, SPAIN SP ARATZ, CAM, CASA, CRISA, ESA, NASA, SENER, SPASA, Nuter sa DE 1809 keV emission; supernovae ID HIGH-VELOCITY AL-26; LINE DATA; DUST; GAS AB Recent observations of the 1809 keV line have indicated that the bulk of the Al-26 must have a velocity of similar to 500 km s(-1) (Naya et al. 1996). We have previously shown that a velocity this large could be maintained over the 10(6) year lifetime of the Al-26 if it is trapped in dust grains that are reaccelerated periodically in the ISM (Sturner & Naya 1999). Here we investigate whether a dust grain velocity of similar to 500 km s(-1) will produce a distribution in latitutde of 1809 keV emission that is consistent with the. distribution seen by COMPTEL. We find that dust grain velocities similar to500 km s(-1) are able to reproduce the, COMPTEL 1809 keV emission maps reconstructed using the Richardson-Lucy and Maximum Entropy image reconstruction methods. The Al-26 production rate Chat is needed to reproduce the observed 1809 keV intensity yields in a Galactic mass of Al-26 of similar to 1.5 - 2 M-circle dot which is in good agreement with both other observations and theoretical production rates. C1 NASA, GSFC, USRA, Greenbelt, MD 20771 USA. RP Sturner, SJ (reprint author), NASA, GSFC, USRA, Greenbelt, MD 20771 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-677-5 J9 ESA SP PUBL PY 2001 VL 459 BP 101 EP 104 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT87A UT WOS:000174318300018 ER PT S AU Valinia, A Tatischeff, V AF Valinia, A Tatischeff, V BE Battrick, B TI A broadband study of the galactic X-ray/gamma-ray background SO EXPLORING THE GAMMA-RAY UNIVERSE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 4th Integral Workshop on Exploring the Gamma-Ray Universe CY SEP 04-08, 2000 CL ALICANTE, SPAIN SP ARATZ, CAM, CASA, CRISA, ESA, NASA, SENER, SPASA, Nuter sa ID K-SHELL IONIZATION; COSMIC-RAYS; EMISSION; PLANE; RIDGE; RADIATION; COMPONENT; CONTINUUM; ELEMENTS; DISK AB We present measurements of the Galactic background radiation in the wide energy bandpass 0.5-1000 keV. We show that in the hard X-ray/soft gamma-ray band, a significant portion of the emission is due to discrete sources. The remaining unresolved emission may be either interpreted as truly diffuse processes or the superposition of discrete sources that have very hard spectra. Here, we show that the unresolved emission may be interproted as nonthermal emission from the interaction of suprathermal electrons with the ambient, interstellar medium. The suprathermal electrons maybe accelerated in supernova explosions or by ambient interstellar plasma turbulence. This interpretation has the advantage that it can naturally explain the complex X-ray line. spectrum of the background emission below 10 keV and the. unresolved omission above 10 keV. Our interpretation is based on measurements taken with ASCA, RXTE and OSSE. Future observations with XMM and INTEGRAL will provide further evidence for the origin of the emission. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Valinia, A (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 45 TC 1 Z9 1 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-677-5 J9 ESA SP PUBL PY 2001 VL 459 BP 153 EP 160 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT87A UT WOS:000174318300028 ER PT S AU Weidenspointner, G Steinle, H AF Weidenspointner, G Steinle, H BE Battrick, B TI An estimate of the contribution of FR I radio galaxies to the extragalactic gamma-ray background SO EXPLORING THE GAMMA-RAY UNIVERSE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 4th Integral Workshop on Exploring the Gamma-Ray Universe CY SEP 04-08, 2000 CL ALICANTE, SPAIN SP ARATZ, CAM, CASA, CRISA, ESA, NASA, SENER, SPASA, Nuter sa DE galaxies : active; galaxies : individual : Cen A; diffuse radiation; gamma rays : observations; gamma rays : theory ID ACTIVE GALACTIC NUCLEI; X-RAY; CENTAURUS-A; UNIFIED SCHEMES; OBJECTS; BLAZARS; COMPTEL AB Recent results on the high-energy extragalactic background radiation suggest that it arises from the superposed emission of unresolved point sources. Seyfert galaxies and blazars have been identified as viable source classes at X-ray energies and high gamma-ray energies, respectively. The situation is less clear in the similar to0.1-10 MeV transition region, where a variety of source populations, among which are supernovae and blazars, are expected to contribute. We present an estimate of the contribution of FR I radio galaxies to the extragalactic gamma-ray background around 1 MeV, based on the FR I radio luminosity function and the high-energy emission properties of the Faranoff-Riley class I radio galaxy Centaurus A. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Weidenspointner, G (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 24 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-677-5 J9 ESA SP PUBL PY 2001 VL 459 BP 353 EP 356 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT87A UT WOS:000174318300073 ER PT S AU Ebisawa, K Kubota, A Mizuno, T Zycki, P AF Ebisawa, K Kubota, A Mizuno, T Zycki, P BE Battrick, B TI Accretion disk spectra of The Ultra-luminous Compact X-ray Sources in nearby spiral galaxies and the super-luminal jet sources SO EXPLORING THE GAMMA-RAY UNIVERSE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 4th Integral Workshop on Exploring the Gamma-Ray Universe CY SEP 04-08, 2000 CL ALICANTE, SPAIN SP ARATZ, CAM, CASA, CRISA, ESA, NASA, SENER, SPASA, Nuter sa DE super-luminal jet sources; ultra-luminous X-ray sources; accretion disks; black holes ID ASCA OBSERVATION; GRO J1655-40; BLACK-HOLES; MASS; BINARIES AB The Ultra-luminous Compact X-ray Sources (ULXs) in nearby spiral galaxies and the Galactic superluminal jet sources share the common spectral characteristic that they have extremely high disk temperatures which cannot be explained in the framework of the standard accretion disk model in the Schwarzschild metric. We examine several possibilities to solve this "too-hot" disk problem. In particular, we have calculated an extreme Kerr disk model to fit the observed spectra. We found that the Kerr disk will become significantly harder compared to the Schwarzschild disk only when the disk is highly inclined. For super-luminal jet sources, which are known to be inclined systems, the Kerr disk model may work if we choose proper values for the black hole angular momentum. For the ULXs, however, the Kerr disk interpretation will be problematic, as it is highly unlikely that their accretion disks are preferentially inclined. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ebisawa, K (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 24 TC 3 Z9 3 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-677-5 J9 ESA SP PUBL PY 2001 VL 459 BP 415 EP 418 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT87A UT WOS:000174318300086 ER PT S AU Weidenspointner, G Harris, MJ Sturner, S Teegarden, B Dean, AJ Diallo, N Shaw, SE AF Weidenspointner, G Harris, MJ Sturner, S Teegarden, B Dean, AJ Diallo, N Shaw, SE BE Battrick, B TI Towards a measurement of the cosmic diffuse gamma-ray background with TGRS SO EXPLORING THE GAMMA-RAY UNIVERSE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 4th Integral Workshop on Exploring the Gamma-Ray Universe CY SEP 04-08, 2000 CL ALICANTE, SPAIN SP ARATZ, CAM, CASA, CRISA, ESA, NASA, SENER, SPASA, Nuter sa DE extragalactic gamma-ray background; TGRS Ge spectrometer; instrumental (line) background ID SPECTROMETER; SUPERNOVAE; ASTRONOMY AB The count rate in the TGRS Ge detector on board WIND contains a large contribution from the cosmic diffuse gamma-ray background due to its large aperture of similar to2pi sterad and due to the fact that instrumental backgrounds are generally lower in WIND's highly elliptical orbit than for near-Earth experiments. If instrumental backgrounds can be eliminated, a measurement of the cosmic diffuse gamma-ray background becomes possible. We give a preliminary demonstration of how as many instrumental background features as possible can eventually be removed, particularly continua arising from beta-decay, Compton scattering, and positron annihilation in the detector, and also the many lines which are resolved by the TGRS Go detector. These techniques may also be useful for removing instrumental backgrounds in SPI/INTEGRAL. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Weidenspointner, G (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-677-5 J9 ESA SP PUBL PY 2001 VL 459 BP 635 EP 638 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT87A UT WOS:000174318300137 ER PT S AU Stecker, FW AF Stecker, FW BE Harwit, M Hauser, MG TI TeV gamma-ray absorption and the intergalactic infrared background SO EXTRAGALACTIC INFRARED BACKGROUND AND ITS COSMOLOGICAL IMPLICATIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union ID STAR-FORMATION HISTORY; COSMIC-RAYS; TENTATIVE DETECTION; LUMINOSITY DENSITY; REDSHIFT SURVEY; IRAS GALAXIES; MKN 501; MU-M; ENERGY; RADIATION AB In this paper, I will take a synoptic approach to determining the intergalactic infrared radiation field (IIRF). This approach draws on both the multi-TeV gamma-ray observations and the infrared background observations and relates them via the semi-empirical modelling method of Malkan & Stecker. I discuss the evidence for an intergalactic infrared background obtained by an analysis of the HEGRA observations of the high energy gamma-ray spectrum of Mrk 501 and from constraints from Mrk 421 deduced from the Whipple air Cherenkov telescope results. I will show that this evidence is in accord with the predictions made by Malkan & Stecker (1998) for the intergalactic infrared spectral energy distribution produced by galaxies. The Malkan-Stecker predictions are also in excellent agreement with mid-infrared galaxy counts. However, there may be potential problems relating these predictions with the results of the analysis of COBE-DIRBE far infrared data. The gamma-ray and COBE-DIRBE observations may also need to be reconciled. I will discuss possible ways to resolve this situation including a partial nullification of the gamma-ray absorption process which can hypothetically occur if Lorentz invariance is broken. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Stecker, FW (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RI Stecker, Floyd/D-3169-2012 NR 55 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-062-5 J9 IAU SYMP PY 2001 IS 204 BP 135 EP 149 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Y UT WOS:000175997600015 ER PT S AU Mushotzky, R AF Mushotzky, R BE Harwit, M Hauser, MG TI X-ray astronomy and the IR background SO EXTRAGALACTIC INFRARED BACKGROUND AND ITS COSMOLOGICAL IMPLICATIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union ID HUBBLE-DEEP-FIELD; 4 RICH CLUSTERS; INTRACLUSTER MEDIUM; ELEMENTAL ABUNDANCES; INTERGALACTIC GAS; ELLIPTIC GALAXIES; ENRICHMENT; EMISSION; REGION; ENERGY AB I review the recent Chandra results on the sources of the X-ray background and the X-ray properties of the SCUBA sources. We conclude that 10-20% of the IR background is produced by active galaxies and a similar fraction of the SCUBA sources harbor luminous AGN. Many of the Chandra sources are apparently luminous infrared galaxies themselves, but factors of 2-10 below the SCUBA limits. We summarize the X-ray evidence for metal production in groups and clusters and point out that these data require considerably more star formation than inferred from optical stellar data. The abundance ratios of Fe and Si indicate that much of the metals in groups and clusters was produced by massive stars, and the lack of evolution in Fe out to z similar to 0.5 argues for quite an early origin for the metals. This same process also seems to have injected considerable energy into the gas in groups and clusters, which may have dominated the mechanism of star formation and produced a metal-enriched intergalactic medium. C1 Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Mushotzky, R (reprint author), Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 41 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-062-5 J9 IAU SYMP PY 2001 IS 204 BP 335 EP 345 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Y UT WOS:000175997600043 ER PT S AU Dwek, E AF Dwek, E BE Harwit, M Hauser, MG TI The role of dust in producing the cosmic infrared background SO EXTRAGALACTIC INFRARED BACKGROUND AND ITS COSMOLOGICAL IMPLICATIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union ID INTERGALACTIC DUST; EMISSION; SUPERNOVAE; RADIATION; EVOLUTION; GALAXIES; ESCAPE AB The extragalactic background light (EBL), exclusive of the cosmic microwave background, consists of the cumulative radiative output from all energy sources in the universe since the epoch of recombination. Most of this energy is released at ultraviolet and optical wavelengths. However, observations show that a significant fraction of the EBL falls in the 10 to 1000,urn wavelength regime. This provides conclusive evidence that we live in a dusty universe, since only dust can efficiently absorbs a significant fraction of the background energy and reemit it at infrared wavelengths. The general role of dust in forming the cosmic infrared background (CIB) is therefore obvious. However, its role in determining the exact spectral shape of the CIB is quite complex. The CIB spectrum depends on the microscopic physical properties of the dust, its composition, abundance, and spatial distribution relative to the emitting sources, and its response to evolutionary processes that can modify all the factors listed above. This paper will present a brief summary of the many ways dust affects the intensity and spectral shape of the cosmic infrared background. In an Appendix we present new limits on the mid-infrared intensity of the CIB using TeV gamma-ray observations of Mrk 501. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Dwek, E (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 22 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-062-5 J9 IAU SYMP PY 2001 IS 204 BP 389 EP 400 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Y UT WOS:000175997600049 ER PT S AU Werner, MW Reach, WT Rieke, M AF Werner, MW Reach, WT Rieke, M BE Harwit, M Hauser, MG TI Studies of the cosmic infrared background with the space infrared telescope facility (SIRTF) SO EXTRAGALACTIC INFRARED BACKGROUND AND ITS COSMOLOGICAL IMPLICATIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union ID RING; DUST AB IRAS, COBE, and ISO have demonstrated the unique importance of a cryogenic infrared telescope in space for studying diffuse infrared backgrounds and for teasing out the individual point sources which contribute to them. This importance results from the extremely high infrared sensitivity of such telescopes, particularly to diffuse radiation. The next cryogenic infrared telescope will be NASA's Space Infrared Telescope Facility (SIRTF), which is currently in the final stages of construction leading to launch in 2002. SIRTF will be the first infrared space observatory to make extensive use - both for imaging and spectroscopy of large format infrared detector arrays. The sensitivity and spatial and spectral coverage of SIRTF's array-based instruments endow SIRTF with great power for the study of the cosmic infrared background (CIRB) and related scientific issues. This paper reviews the SIRTF mission design and measurement functionality and describes SIRTF's potential studies of the CIRB, drawing examples from the programs planned by the SIRTF Guaranteed Time Observers (GTO's). We also summarize the opportunities for community participation in SIRTF. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, SIRTF Sci Ctr, Pasadena, CA 91125 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Werner, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-062-5 J9 IAU SYMP PY 2001 IS 204 BP 439 EP 453 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Y UT WOS:000175997600058 ER PT S AU Stockman, HS Mather, JC AF Stockman, HS Mather, JC BE Harwit, M Hauser, MG TI The Next Generation Space Telescope SO EXTRAGALACTIC INFRARED BACKGROUND AND ITS COSMOLOGICAL IMPLICATIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union ID HUBBLE DEEP FIELD; GALAXY AB The Next Generation Space Telescope (NGST) will be an 8 m deployable telescope, radiatively cooled to 30 K and diffraction-limited at 2 mum, operating at the Sun-Earth Lagrangian point L2. It will be built by a partnership of NASA, ESA, and CSA (Canadian Space Agency). The camera sensitivity should be limited by the zodiacal light for wavelengths < 10 μm. The main scientific objectives are the study of the origin and evolution of galaxies, stars, and planets, beginning with the first luminous objects to form from the Big Bang. Other objectives include studies of dark matter, supernovae, the intergalactic medium, gamma ray bursts, star ages, and exobiology. The telescope will be operated like the Hubble Space Telescope (HST) by the Space Telescope Science Institute, with all observing programs openly solicited and selected by peer review. The NGST. scientific requirements originated with the report of the Dressler Committee HST & Beyond. The instruments recommended by the Ad Hoc Science Working Group (ASWG) include 1) a wide field near infrared (NIR) camera with an 8K(2) detector array covering 0.6 - 5 μm, 2) a multi-object NIR spectrograph capable of simultaneously observing > 100 objects with a resolution of R (lambda/deltalambda) = 1000, and 3) a combined mid-infrared (MIR) camera and spectrograph from 5-27 mum, with a resolution of R > 1500. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Stockman, HS (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. NR 13 TC 0 Z9 1 U1 2 U2 2 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-062-5 J9 IAU SYMP PY 2001 IS 204 BP 467 EP 474 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Y UT WOS:000175997600060 ER PT S AU Mackey, JR Salari, E Spiegelberg, SH AF Mackey, JR Salari, E Spiegelberg, SH BE Marcus, MA Culshaw, B TI Electro-optic force measurement application using phase-modulated optical polarimetry SO FIBER OPTIC SENSOR TECHNOLOGY AND APPLICATIONS 2001 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Fiber Optic Sensor Technology and Applications CY OCT 30-NOV 01, 2001 CL NEWTON, MA SP SPIE DE force; transducer; optical; polarimetry; phase retardance; polymer ID SYSTEM AB In this paper, we describe the design and development of a high sensitivity, large dynamic range force transducer capable of measuring transient force changes in tension and compression. Conventional force transducers typically rely on the deformation of strain gauges, or on servo-mechanical load cells. While strain gauge transducers exhibit a rapid response time, they are subject to electrical noise, and typically have a minimum useful limit of approximately 10(-5) N. Servo-mechanical transducers have poor response times and exhibit compliance in the axis of deformation that is unacceptable for many applications. The research objective is to develop a novel force transducer based on the change in optical properties with loading of a pre-stressed polymer. The concept utilizes a pre-stressed polymer material as a linkage to which a force would be applied either in compression or tension. The molecular deformation of the polymer linkage will be analyzed using miniature optical components arranged as a phase-modulated polarimeter capable of birefringence measurements on the order of 10(-9). Calibration of the measured birefringence with known loads provides the necessary calibration parameters. The instrument is capable of directional force measurements and is extremely accurate for measuring low-level forces. Since the force transducer is based on optical techniques, it would be resistant to electronic noise, and would allow measurement of rapidly changing loads. The best available force transducers capable of measuring transient responses have a lower resolution of approximately 10(-5) N. Research with the rheology of fluids, transient flows of pharmaceuticals in combinatorial research, biological tissue response, and biomimetic adhesive research often require force measurements below this range. Although ultra-microbalances exist that have sensitivities well below this range, the averaging techniques employed that allow these measurements make them unsuitable for transient flows, as does the physical size of the systems. C1 NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. RP Mackey, JR (reprint author), NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Mail Stop 110-3,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4306-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4578 BP 355 EP 365 PG 11 WC Instruments & Instrumentation; Optics SC Instruments & Instrumentation; Optics GA BU25B UT WOS:000175474600038 ER PT S AU Bennett, J El-Sherif, M Froggatt, M AF Bennett, J El-Sherif, M Froggatt, M BE Culshaw, B Harrington, JA Marcus, MA Saad, M TI Transverse loading effects on embedded Bragg fiber system SO FIBER OPTIC SENSOR TECHNOLOGY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Fiber Optic Sensor Technology II CY NOV 06-08, 2000 CL BOSTON, MA SP SPIE DE fiber Bragg grating; embedded optical fiber; Poisson's effect on optical fibers; finite element analysis; optical strain sensors; embedded sensors; smart structures ID INTERFACE; GRATINGS AB Optical fibers imprinted with a Bragg grating, a periodic change in the refractive index of the core of the fiber, can be used as strain gages in structural health monitoring. It is well known that fiber Bragg grating (FBG) structures can be applied as optical strain gages with very high sensitivity and reasonable accuracy. This application has been confirmed through numerous publications on the effect of axial loads on FBG structures. The FBG structure can easily be calibrated as an axial strain sensor. There are currently some trial applications of these optical strain gauges in bridge construction. However, using these FBG structures as embedded sensors has raised questions about sensor accuracy and measurements because of the Poisson's effect and/or application under multi-axial stress states. Therefore, the objective of this research was to study the effect of transverse loads on FBG structures for a better understanding of the interaction of the structure and the embedded Bragg fiber sensor output. C1 NASA, Langley Res Ctr, Nondestruct Evaluat Sci Branch, Hampton, VA 23681 USA. RP Bennett, J (reprint author), NASA, Langley Res Ctr, Nondestruct Evaluat Sci Branch, Hampton, VA 23681 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3869-3 J9 P SOC PHOTO-OPT INS PY 2001 VL 4204 BP 50 EP 60 DI 10.1117/12.417428 PG 11 WC Instruments & Instrumentation; Optics SC Instruments & Instrumentation; Optics GA BS18V UT WOS:000169001500006 ER PT B AU Lowry, MR AF Lowry, MR GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Requirements engineering and program synthesis: Mutually exclusive or synergistic? SO FIFTH IEEE INTERNATIONAL SYMPOSIUM ON REQUIREMENTS ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 5th IEEE International Symposium on Requirements Engineering CY AUG 27-31, 2001 CL TORONTO, CANADA SP IEEE Comp Soc, Inst Elect & Electr Engineers C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM mlowry@mail.arc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1125-2 PY 2001 BP 12 EP 12 PG 1 WC Computer Science, Software Engineering SC Computer Science GA BT70R UT WOS:000173806300004 ER PT B AU Lutz, RR Mikulski, IC AF Lutz, RR Mikulski, IC GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Evolution of safety-critical requirements post-launch SO FIFTH IEEE INTERNATIONAL SYMPOSIUM ON REQUIREMENTS ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 5th IEEE International Symposium on Requirements Engineering CY AUG 27-31, 2001 CL TORONTO, CANADA SP IEEE Comp Soc, Inst Elect & Electr Engineers AB This paper reports the results of a small study of requirements changes to the onboard software of three spacecraft subsequent to launch. Only those requirement changes that resulted from post-launch anomalies (i.e., during operations) were of interest here, since the goal was to better understand the relationship between critical anomalies during operations and how safety-critical requirements evolve. The results of the study were surprising in that anomaly-driven, post-launch requirements changes were rarely due to previous requirements having been incorrect. Instead, changes involved new requirements (1) for the software to handle rare events or (2) for the software to compensate for hardware failures or limitations. The prevalence of new requirements as a result of post-launch anomalies suggests a need for increased requirements-engineering support of maintenance activities in these systems. The results also confirm both the difficulty and the benefits of pursuing requirements completeness, especially in terms of fault tolerance, during development of critical systems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM rlutz@cs.iastate.edu; ines.c.mikulski@jpl.nasa.gov NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1125-2 PY 2001 BP 222 EP 227 PG 6 WC Computer Science, Software Engineering SC Computer Science GA BT70R UT WOS:000173806300028 ER PT B AU Rosenburg, L AF Rosenburg, L GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Requirements management at NASA SO FIFTH IEEE INTERNATIONAL SYMPOSIUM ON REQUIREMENTS ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 5th IEEE International Symposium on Requirements Engineering CY AUG 27-31, 2001 CL TORONTO, CANADA SP IEEE Comp Soc, Inst Elect & Electr Engineers C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM Linda.H.Rosenberg.1@gsfc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1125-2 PY 2001 BP 275 EP 275 PG 1 WC Computer Science, Software Engineering SC Computer Science GA BT70R UT WOS:000173806300044 ER PT B AU Kurtz, T AF Kurtz, T GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Ask Pete, software planning and estimation through project characterization SO FIFTH IEEE INTERNATIONAL SYMPOSIUM ON REQUIREMENTS ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 5th IEEE International Symposium on Requirements Engineering CY AUG 27-31, 2001 CL TORONTO, CANADA SP IEEE Comp Soc, Inst Elect & Electr Engineers AB Ask Pete, was developed by NASA to provide a tool for integrating the estimation and planning activities for a software development effort. It incorporates COCOMO II estimating with NASA's software development practices and IV&V criteria to characterize a project. This characterization is then used to generate estimates and tailored planning documents. C1 NASA, Sci Applicat Int Corp, Glenn Res Ctr, San Diego, CA 92121 USA. RP NASA, Sci Applicat Int Corp, Glenn Res Ctr, San Diego, CA 92121 USA. EM Tim.Kurtz@grc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1125-2 PY 2001 BP 286 EP 286 PG 1 WC Computer Science, Software Engineering SC Computer Science GA BT70R UT WOS:000173806300050 ER PT B AU Feather, MS AF Feather, MS GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Risk reduction using DDP (Defect Detection and Prevention): Software support and software applications SO FIFTH IEEE INTERNATIONAL SYMPOSIUM ON REQUIREMENTS ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 5th IEEE International Symposium on Requirements Engineering CY AUG 27-31, 2001 CL TORONTO, CANADA SP IEEE Comp Soc, Inst Elect & Electr Engineers AB Risk assessment and mitigation is the focus of the Defect Detection and Prevention (DDP) process, which has been applied to spacecraft technology assessments and planning, both hardware and software. DDP's major elements and their relevance to core requirement engineering concerns are summarized. The accompanying research demonstration illustrates DDP's tool support, and further customizations for application to software. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Martin.S.Feather@Jpl.Nasa.Gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1125-2 PY 2001 BP 288 EP 288 PG 1 WC Computer Science, Software Engineering SC Computer Science GA BT70R UT WOS:000173806300052 ER PT B AU Fukumori, I Lee, T Menemenlis, D Fu, LL Cheng, B Tang, BY Xing, ZF Giering, R AF Fukumori, I Lee, T Menemenlis, D Fu, LL Cheng, B Tang, BY Xing, ZF Giering, R GP AMS AMS TI Towards operational ocean state estimation SO FIFTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 5th Symposium on Integrated Observing Systems CY JAN 14-18, 2001 CL ALBUQUERQUE, NM SP Amer Meteorol Soc ID DATA ASSIMILATION; KALMAN FILTER; MODEL C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fukumori, I (reprint author), CALTECH, Jet Prop Lab, MS 300-323, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2001 BP 37 EP 40 PG 4 WC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology SC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology GA BU98Z UT WOS:000177564500010 ER PT B AU Ho, SP Lin, B Minnis, P AF Ho, SP Lin, B Minnis, P GP AMS AMS TI Estimation of cloud properties over oceans using VIRS and TMI measurements on the TRMM satellite SO FIFTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 5th Symposium on Integrated Observing Systems CY JAN 14-18, 2001 CL ALBUQUERQUE, NM SP Amer Meteorol Soc C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Ho, SP (reprint author), NASA, Langley Res Ctr, Mail Stop 936, Hampton, VA 23681 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2001 BP 45 EP 49 PG 5 WC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology SC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology GA BU98Z UT WOS:000177564500012 ER PT B AU Negri, AJ Xu, L Adler, RF AF Negri, AJ Xu, L Adler, RF GP AMS AMS TI A TRMM-calibrated infrared rainfall algorithm applied over Brazil SO FIFTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 5th Symposium on Integrated Observing Systems CY JAN 14-18, 2001 CL ALBUQUERQUE, NM SP Amer Meteorol Soc ID SATELLITE C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Negri, AJ (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 912, Greenbelt, MD 20771 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2001 BP 81 EP 84 PG 4 WC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology SC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology GA BU98Z UT WOS:000177564500020 ER PT B AU Radakovich, JD Houser, PR da Silva, A Bosilovich, MG AF Radakovich, JD Houser, PR da Silva, A Bosilovich, MG GP AMS AMS TI Results from global land-surface data assimilation methods SO FIFTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 5th Symposium on Integrated Observing Systems CY JAN 14-18, 2001 CL ALBUQUERQUE, NM SP Amer Meteorol Soc ID MODELS C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Radakovich, JD (reprint author), NASA, Goddard Space Flight Ctr, Code 910-3, Greenbelt, MD 20771 USA. RI Houser, Paul/J-9515-2013 OI Houser, Paul/0000-0002-2991-0441 NR 5 TC 3 Z9 3 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2001 BP 132 EP 134 PG 3 WC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology SC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology GA BU98Z UT WOS:000177564500032 ER PT B AU Walker, JP Houser, PR AF Walker, JP Houser, PR GP AMS AMS TI A synthetic study on the influence of error in surface soil moisture observations on assimilation SO FIFTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 5th Symposium on Integrated Observing Systems CY JAN 14-18, 2001 CL ALBUQUERQUE, NM SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Walker, JP (reprint author), NASA, Goddard Space Flight Ctr, Code 974, Greenbelt, MD 20771 USA. RI Houser, Paul/J-9515-2013 OI Houser, Paul/0000-0002-2991-0441 NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2001 BP 135 EP 138 PG 4 WC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology SC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology GA BU98Z UT WOS:000177564500033 ER PT B AU Entin, JK Houser, PR Cosgrove, BA AF Entin, JK Houser, PR Cosgrove, BA GP AMS AMS TI Data assimilation of surface and satellite observations to improve land surface modeling SO FIFTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 5th Symposium on Integrated Observing Systems CY JAN 14-18, 2001 CL ALBUQUERQUE, NM SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Entin, JK (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Mail Code 974, Greenbelt, MD 20771 USA. RI Houser, Paul/J-9515-2013 OI Houser, Paul/0000-0002-2991-0441 NR 0 TC 0 Z9 0 U1 0 U2 3 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2001 BP 167 EP 167 PG 1 WC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology SC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology GA BU98Z UT WOS:000177564500042 ER PT B AU Lord, SJ Masutani, M Woollen, JS Derber, JC Atlas, R Terry, J Emmitt, GD Wood, SA Greco, S Kleespies, TJ Kapoor, V AF Lord, SJ Masutani, M Woollen, JS Derber, JC Atlas, R Terry, J Emmitt, GD Wood, SA Greco, S Kleespies, TJ Kapoor, V GP AMS AMS TI Observing system simulation experiments for NPOESS SO FIFTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 5th Symposium on Integrated Observing Systems CY JAN 14-18, 2001 CL ALBUQUERQUE, NM SP Amer Meteorol Soc ID LARGE-SCALE MODELS C1 NASA, Goddard Space Flight Ctr, DAO, Greenbelt, MD USA. RP Lord, SJ (reprint author), NASA, Goddard Space Flight Ctr, DAO, Greenbelt, MD USA. NR 26 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2001 BP 168 EP 175 PG 8 WC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology SC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology GA BU98Z UT WOS:000177564500043 ER PT B AU Smith, GL AF Smith, GL GP AMS AMS TI Earth-emitted irradiance at Triana SO FIFTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 5th Symposium on Integrated Observing Systems CY JAN 14-18, 2001 CL ALBUQUERQUE, NM SP Amer Meteorol Soc ID RADIATION C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Smith, GL (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2001 BP 179 EP 181 PG 3 WC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology SC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology GA BU98Z UT WOS:000177564500045 ER PT B AU Huffman, GJ Adler, RF Bolvin, DT Curtis, S AF Huffman, GJ Adler, RF Bolvin, DT Curtis, S GP AMS AMS TI The role of combination techniques in maximizing the utility of precipitation estimates from several multi-purpose remote-sensing systems SO FIFTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 5th Symposium on Integrated Observing Systems CY JAN 14-18, 2001 CL ALBUQUERQUE, NM SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Huffman, GJ (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2001 BP 229 EP 230 PG 2 WC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology SC Meteorology & Atmospheric Sciences; Imaging Science & Photographic Technology GA BU98Z UT WOS:000177564500055 ER PT B AU Hood, R Matthews, G AF Hood, R Matthews, G BE Buyya, R Mohay, G Roe, P TI Efficient tracing for on-the-fly space-time displays in a debugger for message passing programs SO FIRST IEEE/ACM INTERNATIONAL SYMPOSIUM ON CLUSTER COMPUTING AND THE GRID, PROCEEDINGS LA English DT Proceedings Paper CT 1st IEEE/AMC International Symposium on Cluster Computing and the Grid CY MAY 15-18, 2001 CL BRISBANE, AUSTRALIA SP IEEE, Comp Soc, IEEE Comp Soc, Task Force Cluster Comp, Assoc Comp Mach, SIGARCH, IEEE Comp Soc, Tech Comm Parallel Proc, Queensland Univ Technol ID PARALLEL AB In this work we describe the implementation of a practical mechanism for collecting and displaying trace information in a debugger for message passing programs. We introduce a trace format that is highly compressible while still providing information adequate for debugging purposes. We make the mechanism convenient for users to access by incorporating the trace collection in a set of wrappers for the MPI communication library. We implement several debugger operations that use the trace display: consistent stoplines, undo, and rollback. They all are implemented using controlled replay, which executes at fill speed in target processes until the appropriate position in the computation is reached. They provide convenient mechanisms for getting to places in the execution where the full power of a state-based debugger can be brought to bear on isolating communication errors. C1 Comp Sci Corp, NASA, Ames Res Ctr, Cincinnati, OH 45202 USA. RP Hood, R (reprint author), Comp Sci Corp, NASA, Ames Res Ctr, Cincinnati, OH 45202 USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1011-6 PY 2001 BP 394 EP 403 DI 10.1109/CCGRID.2001.923219 PG 10 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BT38Z UT WOS:000172837500058 ER PT S AU Chernov, AA AF Chernov, AA BE Schurmann, B TI Merging microgravity research with general material and biological sciences SO FIRST INTERNATIONAL SYMPOSIUM ON MICROGRAVITY RESEARCH & APPLICATIONS IN PHYSICAL SCIENCES AND BIOTECHNOLOGY, VOLS I AND II, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 1st International Symposium on Microgravity Research and Applications in Physical Sciences and Biotechnology CY SEP 10-15, 2000 CL SORRENTO, ITALY SP European Space Agcy, Seconda Univ Napoli, ASI, CNES, CSA, DLR, NASA, NASDA C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35806 USA. RP Chernov, AA (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, 4950 Corp Dr,Ste 100, Huntsville, AL 35806 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-657-0 J9 ESA SP PUBL PY 2001 VL 454 BP 15 EP 16 PG 2 WC Engineering, Aerospace; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Fluids & Plasmas SC Engineering; Materials Science; Metallurgy & Metallurgical Engineering; Physics GA BS85H UT WOS:000171226000002 ER PT S AU Sacksteder, KR AF Sacksteder, KR BE Schurmann, B TI The behavior of flames spreading over thin and thick solid fuels in oxygen-enriched, quiescent atmospheres: Experiments in earth-orbiting facilities and comparative modeling and numerical simulations SO FIRST INTERNATIONAL SYMPOSIUM ON MICROGRAVITY RESEARCH & APPLICATIONS IN PHYSICAL SCIENCES AND BIOTECHNOLOGY, VOLS I AND II, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 1st International Symposium on Microgravity Research and Applications in Physical Sciences and Biotechnology CY SEP 10-15, 2000 CL SORRENTO, ITALY SP European Space Agcy, Seconda Univ Napoli, ASI, CNES, CSA, DLR, NASA, NASDA ID MICROGRAVITY; ENVIRONMENT AB This paper provides a summary of the results of flame spread experiments conducted aboard the NASA Space Shuttle, and of numerical simulations of flame spreading phenomena in quiescent environments. Since these flames spread into a quiescent fresh oxidizer, they are considered the limiting case of opposed-flow flame spread. Experiments were conducted using a space-flight payload, the Solid Surface Combustion Experiment, or SSCE. The SSCE apparatus provided an enclosed volume of 0.039 m(3) that was filled before launch with the fuel sample(s) and the desired test atmosphere, varying in pressure from 1-2 atmospheres and oxygen mole fractions from 35% to 70%, balance nitrogen. Thin-fuel flame spread was observed using ashless filter paper samples; thick fuel was flat slabs and cylinders of Polymethylmethacrylate, or PMMA. Under enriched oxygen conditions flames ignite and spread steadily over thin fuels. Thick fuels are ignitable; and while the flames may ultimately quench, they may spread and release substantial heat and reaction product gases for minutes before quenching. In each of these reduced-gravity flame spread regimes, the limiting finite-rate flame chemical kinetics are retarded by diffusional and radiative mechanisms. These experimental results and simulations form an important part of the microgravity flame spreading knowledge base from which ongoing developments in extra-terrestrial fire safety engineering are to evolve. C1 NASA, Glenn Res Ctr, Micrograv Sci Div, Cleveland, OH 44135 USA. RP Sacksteder, KR (reprint author), NASA, Glenn Res Ctr, Micrograv Sci Div, 21000 Brookpk Rd,MS 500-115, Cleveland, OH 44135 USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-657-0 J9 ESA SP PUBL PY 2001 VL 454 BP 259 EP 265 PG 7 WC Engineering, Aerospace; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Fluids & Plasmas SC Engineering; Materials Science; Metallurgy & Metallurgical Engineering; Physics GA BS85H UT WOS:000171226000037 ER PT S AU Kassemi, M Barsi, S AF Kassemi, M Barsi, S BE Schurmann, B TI Effects of thermocapillary mixing generated by voids on microgravity segregation patterns SO FIRST INTERNATIONAL SYMPOSIUM ON MICROGRAVITY RESEARCH & APPLICATIONS IN PHYSICAL SCIENCES AND BIOTECHNOLOGY, VOLS I AND II, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 1st International Symposium on Microgravity Research and Applications in Physical Sciences and Biotechnology CY SEP 10-15, 2000 CL SORRENTO, ITALY SP European Space Agcy, Seconda Univ Napoli, ASI, CNES, CSA, DLR, NASA, NASDA AB Three recent microgravity experiments have been hampered by convection caused by unwanted voids and/or bubbles in the melt. In this work, we present a numerical study to describe how thermocapillary convection generated by a void or bubble can affect a typical microgravity solidification process. A detailed numerical model for the Bridgman solidification of a doped single crystal from its dilute binary melt is developed which solves the quasi-steady Navier Stokes equations together with the conservation equations for transport of energy and species. The complicating effects of thermocapillary convection generated by the void and solutal rejection at the melt-solid interface are included. Numerical simulations indicate that void-generated thermocapillary convection can affect segregation patterns drastically, especially, if the thermocapillary vortex penetrates the solutal boundary layer at the growth interface. Two lateral void positions are considered with the void placed either in the center of the ampoule or on the side wall. From a transport point of view, three different segregation regimes are identified for each lateral void location based on the distance between the void and the growth interface. These range from a diffusion-controlled regime where most of the radial nonuniformity in the interfacial composition is due to the interface curvature with minimal convective effects to a fully mixed regime where the penetration of the solutal boundary layer by the thermocapillary vortex tends to homogenize the interfacial compositions drastically. Naturally, the extent of each of these regions will not only depend on the size and lateral position of the void but also on the material and growth properties of the system under consideration. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Kassemi, M (reprint author), NASA, Glenn Res Ctr, NCMR MS 110-1,21000 Brook Pk Rd, Cleveland, OH 44135 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-657-0 J9 ESA SP PUBL PY 2001 VL 454 BP 409 EP 416 PG 8 WC Engineering, Aerospace; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Fluids & Plasmas SC Engineering; Materials Science; Metallurgy & Metallurgical Engineering; Physics GA BS85H UT WOS:000171226000056 ER PT S AU Liu, FC Larson, M Pensinger, J AF Liu, FC Larson, M Pensinger, J BE Schurmann, B TI Scientific research on the Low Temperature Microgravity Physics Facility on ISS SO FIRST INTERNATIONAL SYMPOSIUM ON MICROGRAVITY RESEARCH & APPLICATIONS IN PHYSICAL SCIENCES AND BIOTECHNOLOGY, VOLS I AND II, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 1st International Symposium on Microgravity Research and Applications in Physical Sciences and Biotechnology CY SEP 10-15, 2000 CL SORRENTO, ITALY SP European Space Agcy, Seconda Univ Napoli, ASI, CNES, CSA, DLR, NASA, NASDA ID HIGH-RESOLUTION MEASUREMENTS; SUPERFLUID TRANSITION; HEAT-CAPACITY; LAMBDA-POINT; HE-4; HELIUM AB A hallmark for fundamental physics research at low temperature is the ultra-high measurement precision. Recent advancements in measurement techniques have reached the extent that gravity is the only limiting factor in many areas of research at low temperature. Thus the Low Temperature Microgravity Physics Facility (LTMPF) on the ISS will expand the frontier, and provide scientists an unique research opportunity. The LTMPF is a state-of-the-art facility for long duration science investigations whose objectives can only be achieved in microgravity and at low temperature. It is a self contained, reusable, cryogenic facility that will accommodate a series of low temperature experiments to be conducted on the Japanese Experiment Module Exposed Facility (JEM-EF) of the ISS, with a cryogen lifetime of about five months. This paper will describe areas of research planned for early missions of LTMPF, as well as LTMPF science requirements, design capabilities and current status. Opportunities for utilization and collaboration will also be discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liu, FC (reprint author), CALTECH, Jet Prop Lab, MS 79-5,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 0 Z9 0 U1 1 U2 1 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-657-0 J9 ESA SP PUBL PY 2001 VL 454 BP 787 EP 789 PG 3 WC Engineering, Aerospace; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Fluids & Plasmas SC Engineering; Materials Science; Metallurgy & Metallurgical Engineering; Physics GA BS85H UT WOS:000171226000103 ER PT S AU Israelsson, UE Lee, MC AF Israelsson, UE Lee, MC BE Schurmann, B TI New microgravity fundamental physics research areas in the ISS era SO FIRST INTERNATIONAL SYMPOSIUM ON MICROGRAVITY RESEARCH & APPLICATIONS IN PHYSICAL SCIENCES AND BIOTECHNOLOGY, VOLS I AND II, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 1st International Symposium on Microgravity Research and Applications in Physical Sciences and Biotechnology CY SEP 10-15, 2000 CL SORRENTO, ITALY SP European Space Agcy, Seconda Univ Napoli, ASI, CNES, CSA, DLR, NASA, NASDA AB NASA's microgravity fundamental physics program has used the Space Shuttle to perform high resolutions experiments in space. As we come to the end of the Shuttle era, we will begin to perform research aboard the ISS. A large stable of ground based experiments have been selected from NASA Research Announcements in a variety of disciplines. These investigations will form the backbone from which to select future flight candidates. Research in Laser Cooling and Atomic Physics will enable us to operate highly precise clocks in space. Low temperature physics experiments will use a liquid helium facility with a six-month lifetime. This facility can also support experiments in gravitational physics. Researchers in biological physics will be offered an opportunity to develop future experiments that can benefit from space experimentation. An overview of the future research directions and the benefits to the community of performing research aboard the ISS will be presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Israelsson, UE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mailstop 233-200, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-657-0 J9 ESA SP PUBL PY 2001 VL 454 BP 791 EP 795 PG 5 WC Engineering, Aerospace; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Fluids & Plasmas SC Engineering; Materials Science; Metallurgy & Metallurgical Engineering; Physics GA BS85H UT WOS:000171226000104 ER PT S AU Ramachandran, N AF Ramachandran, N BE Schurmann, B TI Understanding g-jitter fluid mechanics by modeling and experiments SO FIRST INTERNATIONAL SYMPOSIUM ON MICROGRAVITY RESEARCH & APPLICATIONS IN PHYSICAL SCIENCES AND BIOTECHNOLOGY, VOLS I AND II, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 1st International Symposium on Microgravity Research and Applications in Physical Sciences and Biotechnology CY SEP 10-15, 2000 CL SORRENTO, ITALY SP European Space Agcy, Seconda Univ Napoli, ASI, CNES, CSA, DLR, NASA, NASDA AB While there is a general understanding of the acceleration environment onboard an orbiting spacecraft, past research efforts in the modeling and analysis area have still not produced a general theory that predicts the effects of multispectral periodic accelerations on a general class of experiments nor have they produced scaling laws that a prospective experimenter can use to assess how an experiment might be affected by this acceleration environment. Further-more, there are no actual flight experimental data that correlates heat or mass transport with measurements of the periodic acceleration environment. The present investigation approaches this problem with carefully conducted terrestrial experiments and rigorous numerical modeling for better understanding the effect of residual gravity and g-jitter on experiments. The approach is to use magnetic fluids that respond to an imposed magnetic field gradient in much the same way as fluid density responds to a gravitational field. By utilizing a programmable power source in conjunction with an electromagnet, both static and dynamic body forces can be simulated in lab experiments. The paper provides an overview of the technique and includes recent results from the experiments. The analytical and modeling effort provides the theoretical framework for the investigation. The validity of the commonly used Oberbeck-Boussinesq approximation is also tested and preliminary results are presented. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Ramachandran, N (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, SD47, Huntsville, AL 35812 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-657-0 J9 ESA SP PUBL PY 2001 VL 454 BP 925 EP 931 PG 7 WC Engineering, Aerospace; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Fluids & Plasmas SC Engineering; Materials Science; Metallurgy & Metallurgical Engineering; Physics GA BS85H UT WOS:000171226000122 ER PT S AU Kierk, I Hahn, I Lauver, RW Kohl, FJ Schiller, P Dieckmann, M Becker, J Lazegers, M Brisson, P Grabenhofer, J AF Kierk, I Hahn, I Lauver, RW Kohl, FJ Schiller, P Dieckmann, M Becker, J Lazegers, M Brisson, P Grabenhofer, J BE Schurmann, B TI A survey of selected ESA and NASA new technologies within the microgravity facilities on board the International Space Station and beyond SO FIRST INTERNATIONAL SYMPOSIUM ON MICROGRAVITY RESEARCH & APPLICATIONS IN PHYSICAL SCIENCES AND BIOTECHNOLOGY, VOLS I AND II, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 1st International Symposium on Microgravity Research and Applications in Physical Sciences and Biotechnology CY SEP 10-15, 2000 CL SORRENTO, ITALY SP European Space Agcy, Seconda Univ Napoli, ASI, CNES, CSA, DLR, NASA, NASDA ID LIGHT-SCATTERING; SIZE AB This paper presents an overview of the European Space Agency (ESA) and National Aeronautics and Space Administration (NASA) selected new technologies, planned to contribute to microgravity research on board the International Space Station (ISS), and discusses new technology development trends during and beyond the ISS era. It also introduces ESA and NASA exhibits of the individual microgravity research approaches for combustion, fluid physics, and fundamental physics research disciplines and related technologies. The main purpose of our paper is to introduce and discuss selected sample technologies, planned within the ISS facilities, to the international science community prior to the first International Announcement of Opportunity (AO) in order to help the proposing researchers to take advantage of what will be available to them for conducting their experiments. As a result of this discussion, we expect an exchange of vital technical information between ESA and NASA leading to a broader, stronger and closer international collaboration in the near future. C1 CALTECH, NASA, Jet Propuls Lab, Pasadena, CA 91106 USA. RP Kierk, I (reprint author), CALTECH, NASA, Jet Propuls Lab, 4800 Oak Grove Dr,MS 233 200, Pasadena, CA 91106 USA. NR 22 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-657-0 J9 ESA SP PUBL PY 2001 VL 454 BP 951 EP 964 PG 14 WC Engineering, Aerospace; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Fluids & Plasmas SC Engineering; Materials Science; Metallurgy & Metallurgical Engineering; Physics GA BS85H UT WOS:000171226000125 ER EF